Sea Encounters
Choose one of these 19 sea encounters, read its opening aloud, and start playing. Each gives a concrete setup, a trigger, actions, consequences, and ways to finish or withdraw.
Each Setup includes an expandable DM hex map with a numbered key and a printable SVG download. Adjacent hex centers are 5 feet apart, with north up. Maps include DM information. Unstated dimensions and placements are illustrative; stated distances and encounter text take precedence. On outdoor maps, the dashed outer edge marks the illustrated area, not a wall. Heights and depths appear in the key.
Choose an Encounter
Suggested levels assume four adventurers with some resources remaining; they are starting points, not guaranteed difficulty ratings. Times estimate minutes of table play. Peaceful scenes can fit other levels; check the listed creature if a fight starts.
| Encounter | Levels | Type | Time | Immediate problem |
|---|---|---|---|---|
| 1. Harpy’s Deception | 4–6 | Rescue / combat | 20–30 | A song from a rocky perch threatens a shoreline landing. |
| 2. Kraken’s Distant Reach | Any | Ship hazard / escape | 15–25 | A vast creature’s distant movement sends spars against the ship. |
| 3. Ghost Ship Apparition | 4–6 | Social / possible combat | 20–30 | A silent dead captain wants a manifest returned. |
| 4. Merfolk Diplomacy | 2–5 | Social / rescue | 15–25 | A delegation asks for a fishing net cut from its public channel. |
| 5. Sea Serpent Chase | 5–8 | Pursuit / combat | 20–30 | A large marine predator follows a leaking fish barrel. |
| 6. Coral Reef Maze | 2–5 | Navigation hazard | 15–25 | A grounded keel needs a marked channel to be sounded. |
| 7. Goblin Boat Raid | 3–5 | Social / combat | 20–30 | Small pirates demand one cargo crate from two rowing boats. |
| 8. Jellyfish Drift | 2–5 | Navigation / hazard | 15–20 | A visible stinging drift blocks swimming near the hull. |
| 9. Leviathan’s Wake | 3–6 | Deck hazard | 10–20 | A distant giant animal’s wake threatens unsecured cargo. |
| 10. Shipwreck Survivor | Any | Rescue / social | 15–20 | A survivor clings to floating timber with a sealed message. |
| 11. Maelstrom Madness | 4–7 | Timed ship hazard | 20–25 | A visible current ring demands coordinated departure tasks. |
| 12. Sea Gate Sphinx | 7–10 | Puzzle / social | 15–25 | A shore guardian offers a riddle or a practical repair. |
| 13. Sea Hag’s Bargain | 5–8 | Social / dangerous combat | 20–30 | A shore hag claims a stolen bell belongs to her. |
| 14. Sunken Temple Discovery | 4–6 | Underwater exploration | 20–30 | Guides offer access to a shallow ruin in exchange for recovery work. |
| 15. Ship-Devouring Whirlpool | 5–8 | Hazard / salvage | 20–30 | A wreck’s mooring cable pulls the ship toward a visible vortex. |
| 16. Shore Fey Revelry | 2–5 | Social | 15–25 | Revelers on a sandbar ask the crew to carry a lost instrument home. |
| 17. Shipwrecked Undead | 4–6 | Combat / remembrance | 20–30 | Three drowned sentries guard a sealed crew manifest. |
| 18. Aquatic Elemental Disturbance | 5–8 | Repair / combat | 20–30 | A living current circles a broken harbor sluice. |
| 19. Deep-Sea Leviathan Warning | Any | Navigation / decision | 15–25 | A deep disturbance forces a choice between soundings and a safe detour. |
Running This Collection
Use SRD 5.1 creature statistics; expand a reference inside each scene for the actual attacks, defenses, senses, and actions. HP is per creature. A damage entry such as 4 (1d4 + 2) means use the average or roll, not both. A weapon range of 30/120 means normal/long range; attacks beyond normal range have disadvantage. Use listed ability modifiers for unlisted checks or saves. All references are freely available under CC BY 4.0.
Original procedures: scene-specific checks, timers, magical scenery, bargains, and hazard damage below are original design, not universal official rules or extra creature abilities. Use a stated check only when its approach is uncertain; a sound plan that removes the danger can succeed without rolling. Roll initiative before hostile actions, apply hiding and surprise normally, and do not treat dim light as physical cover. Melee reach and multiattack limits are in the references. Unless specified, scenes occur by daylight outdoors; dark interiors need a light source.
At sea: distances describe a 60-by-20-foot ship’s deck or a nearby shore unless a scene gives another layout. Assume six ordinary sailors handle routine sailing; they are not extra combatants. Ship handling checks below are original scene procedures, not a naval combat system. Deck rails, a carried 50-foot rescue line, and a reachable fallback shore are present unless stated otherwise. Use underwater combat when fighting submerged; aquatic beasts do not gain a land speed or new attacks.
1. Harpy’s Deception
At a glance: levels 4–6 | Rescue / combat | 20–30 minutes | Creatures: 1 × Harpy.
A beautiful song drifts across the landing. A winged figure watches from a low rock beside the water.
Setup. The ship anchors 400 feet south of a 30-by-60-foot landing, keeping its sailors outside the song’s 300-foot range. Adventurers arrive by tender at the south edge, with a secured 50-foot rescue line. One harpy perches 10 feet up, 40 feet north. Rocks and the retreating tender are visible before the song begins.
DM hex map: Harpy's Deception
Trigger. When adventurers approach the bow, roll initiative before the harpy uses Luring Song.
Run it. Use the actual song’s hearing, save, movement, danger-save, and immunity limits. Charmed creatures do not silently leap into certain death without the printed dangerous-terrain save. Allies can use secured lines or move a willing rescued person normally. The harpy flees at half HP. Its siren-like role adds no shipbreaking attack.
Resolution and reward. The landing cache holds 40 gp and a harbor pilot’s chart. Silencing or driving it away clears the landing; sailing around takes 30 minutes.
Adjust. Easier: the harpy leaves when warned. Harder: its perch provides half cover from the bow.
SRD reference: Harpy
Medium monstrosity, chaotic evil
AC 11 | HP 38 (7d8 + 7) | Speed 20 ft., fly 40 ft. | CR 1 (200 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 12 (+1) | 13 (+1) | 12 (+1) | 7 (−2) | 10 (+0) | 13 (+1) |
- Senses: passive Perception 10
- Languages: Common
Actions
Multiattack. The harpy makes two attacks: one with its claws and one with its club.
Claws. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 6 (2d4 + 1) slashing damage.
Club. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 3 (1d4 + 1) bludgeoning damage.
Luring Song. The harpy sings a magical melody. Every humanoid and giant within 300 feet of the harpy that can hear the song must succeed on a DC 11 Wisdom saving throw or be charmed until the song ends. The harpy must take a bonus action on its subsequent turns to continue singing. It can stop singing at any time. The song ends if the harpy is incapacitated. While charmed by the harpy, a target is incapacitated and ignores the songs of other harpies. If the charmed target is more than 5 feet away from the harpy, the target must move on its turn toward the harpy by the most direct route, trying to get within 5 feet. It doesn’t avoid opportunity attacks, but before moving into damaging terrain, such as lava or a pit, and whenever it takes damage from a source other than the harpy, the target can repeat the saving throw. A charmed target can also repeat the saving throw at the end of each of its turns. If the saving throw is successful, the effect ends on it. A target that successfully saves is immune to this harpy’s song for the next 24 hours.
2. Kraken’s Distant Reach
At a glance: levels Any | Ship hazard / escape | 15–25 minutes | Creatures: No combat creatures.
Tentacles rise far beyond the bow. A snapped boom sweeps toward your rigging on the next swell.
Setup. The anchored ship lies 200 feet from a visible southern harbor mouth. The creature remains distant scenery: this original escape hazard uses no invented weakened kraken stat block or direct monster attacks.
DM hex map: Kraken's Distant Reach
Trigger. A lookout spots the moving boom; roll initiative for a three-round departure.
Run it. An action releasing the anchor line, one action clearing the bow cable, and one helm action aim the ship south. Three completed tasks let the crew sail clear on count 0 round 3. If unfinished, a boom strikes one marked 10-foot deck section: DC 13 Dexterity, 2d6 bludgeoning on failure, half on success. The ship remains afloat and tasks can be completed afterward.
Resolution and reward. Escape preserves the ship and reveals a drifting 30 gp cargo crate at the harbor mouth. No fight with a full kraken is required.
Adjust. Easier: anchor is already raised. Harder: one task needs two helpers at separated stations.
3. Ghost Ship Apparition
At a glance: levels 4–6 | Social / possible combat | 20–30 minutes | Creatures: 1 × Specter.
A pale vessel drifts alongside without a wake. Its captain points from an empty ledger stand to a floating waterproof case.
Setup. The party’s ship is anchored 20 feet south of an original spectral deck that can support willing visitors during this scene. One specter stands aboard; a case floats on a rescue line within 10 feet. Boarding is voluntary.
DM hex map: Ghost Ship Apparition
Trigger. The captain gestures to the case and never speaks, matching the specter’s limitations.
Run it. Pulling the case aboard takes an action. Placing its manifest on the stand releases the apparition and captain. Attacking or stealing the manifest triggers actual Life Drain, including its maximum-HP save; returning it still ends hostility. Leaving the ship unboarded is safe. Its spectral appearance does not give the specter new spells or a summoned crew.
Resolution and reward. The case’s separate coin compartment holds 50 gp, indicated before the vessel fades. The deck remains until visitors have safely left.
Adjust. Easier: case is already on the rail. Longer: read three lost sailors’ names before returning the manifest.
SRD reference: Specter
Medium undead, chaotic evil
AC 12 | HP 22 (5d8) | Speed 0 ft., fly 50 ft. (hover) | CR 1 (200 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 1 (−5) | 14 (+2) | 11 (+0) | 10 (+0) | 10 (+0) | 11 (+0) |
- Damage Resistances: acid, cold, fire, lightning, thunder; bludgeoning, piercing, and slashing from nonmagical attacks
- Damage Immunities: necrotic, poison
- Condition Immunities: charmed, exhaustion, grappled, paralyzed, petrified, poisoned, prone, restrained, unconscious
- Senses: darkvision 60 ft., passive Perception 10
- Languages: understands all languages it knew in life but can’t speak
Incorporeal Movement. The specter can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.
Sunlight Sensitivity. While in sunlight, the specter has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.
Actions
Life Drain. Melee Spell Attack: +4 to hit, reach 5 ft., one creature. Hit: 10 (3d6) necrotic damage. The target must succeed on a DC 10 Constitution saving throw or its hit point maximum is reduced by an amount equal to the damage taken. This reduction lasts until the creature finishes a long rest. The target dies if this effect reduces its hit point maximum to 0.
4. Merfolk Diplomacy
At a glance: levels 2–5 | Social / rescue | 15–25 minutes | Creatures: 3 × Merfolk.
Three figures rise beside the hull and hold up a severed mesh line. One points toward a red buoy.
Setup. The anchored ship lies 30 feet south of a shallow channel marked by the buoy. Three merfolk wait at the rail; the net lies 5 feet below the surface. Their listed languages, Aquan and Common, permit negotiation.
DM hex map: Merfolk Diplomacy
Trigger. They ask the crew to stop hauling until the net is freed.
Run it. A blade on a pole or a tethered swimmer can cut three marked support knots, one action each, without an attack roll. Each visitor can use a secured line for retrieval. The merfolk protect the swimmer from drifting gear but are not extra underwater attack bonuses. Refusal prompts them to block further net hauling, not automatically sink the ship.
Resolution and reward. Opening the channel earns a 25 gp pearl and directions through the next reef. The salvaged net remains ordinary damaged gear.
Adjust. Easier: two knots already broke. Longer: negotiate compensation with the fishing crew as well.
SRD reference: Merfolk
Medium humanoid (merfolk), neutral
AC 11 | HP 11 (2d8 + 2) | Speed 10 ft., swim 40 ft. | CR 1/8 (25 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 10 (+0) | 13 (+1) | 12 (+1) | 11 (+0) | 11 (+0) | 12 (+1) |
- Skills: Perception +2
- Senses: passive Perception 12
- Languages: Aquan, Common
Amphibious. The merfolk can breathe air and water.
Actions
Spear. Melee or Ranged Weapon Attack: +2 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 3 (1d6) piercing damage, or 4 (1d8) piercing damage if used with two hands to make a melee attack.
5. Sea Serpent Chase
At a glance: levels 5–8 | Pursuit / combat | 20–30 minutes | Creatures: 1 × Plesiosaurus.
A long neck follows the ship’s wake. Beneath the stern, fish spill steadily from a cracked barrel.
Setup. The ship moves toward a visible southern cove 200 feet away. One plesiosaurus starts 40 feet astern. Use the actual beast rather than an invented giant sea serpent; it has no coil, swallow, or shipcrushing action.
DM hex map: Sea Serpent Chase
Trigger. It bites an accessible target only after coming within its printed reach.
Run it. Releasing the leaking barrel with an action draws it off for 1 minute, letting the ship reach the cove. Repairing the barrel takes two actions and ends the scent trail, after which it gives up in 3 rounds if not attacked. If fighting, use its normal movement and Bite, without free attacks from pursuit narration.
Resolution and reward. The saved cargo is worth 30 gp to the quartermaster; discarding one barrel reduces that payment to 20 gp but resolves the danger.
Adjust. Easier: barrel release is already rigged. Harder: moving a crate blocks access to the leaking barrel for one action.
SRD reference: Plesiosaurus
Large beast, unaligned
AC 13 (natural armor) | HP 68 (8d10 + 24) | Speed 20 ft., swim 40 ft. | CR 2 (450 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 18 (+4) | 15 (+2) | 16 (+3) | 2 (−4) | 12 (+1) | 5 (−3) |
- Skills: Perception +3, Stealth +4
- Senses: passive Perception 13
- Languages: —
Hold Breath. The plesiosaurus can hold its breath for 1 hour.
Actions
Bite. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 14 (3d6 + 4) piercing damage.
6. Coral Reef Maze
At a glance: levels 2–5 | Navigation hazard | 15–25 minutes | Creatures: No combat creatures.
The keel grinds once, then stops. Pale coral shapes divide the water into three visible channels.
Setup. The ship rests safely in shallow water 100 feet from a southern sandy anchorage. Three lanes north are marked by red, white, and blue posts. The blue lane has visible deep-water ripples; no monsters wait beneath the hull.
DM hex map: Coral Reef Maze
Trigger. The captain asks for a sound channel before ordering the next move.
Run it. A pole sounding from the bow, or a tethered swimmer with a lead line, identifies blue as safe in 10 minutes without a roll. A rushed DC 13 Survival check chooses immediately; failure grounds the ship again, costing 30 minutes, without sinking it. An action shifting two deck crates to the stern helps free the keel.
Resolution and reward. Passage through blue reveals a 25 gp salvage bundle on an exposed sandbar. Choosing to anchor and wait for tide costs 2 hours instead.
Adjust. Easier: a merfolk-made depth mark is visible. Harder: shift three crates rather than two.
7. Goblin Boat Raid
At a glance: levels 3–5 | Social / combat | 20–30 minutes | Creatures: 3 × .
Two low boats draw alongside. A goblin holds up an empty food sack and points at the cargo hatch.
Setup. The anchored ship has clear water south and a sandy west shore 50 feet away. Three goblins occupy two ordinary rowboats, 20 feet from the rail. They replace aquatic goblins on invented mounts, gaining no water breathing or shark control.
DM hex map: Goblin Boat Raid
Trigger. They demand one food crate worth 5 gp before attempting to board.
Run it. Payment or a smaller food offer with DC 12 Persuasion ends the raid. If attacked, goblins fire shortbows and use ropes to board on their own turns, not free narration. A boat at the rail can be pushed off with an action and DC 12 Strength, an original boarding procedure; occupants are not automatically drowned. They flee after one falls.
Resolution and reward. Their lead boat holds a stolen harbor map and 18 gp. Returning the map earns a pilot contact.
Adjust. Easier: 2 goblins. Harder: 4, with both boats visible throughout negotiation.
SRD reference: Goblin
Small humanoid (goblinoid), neutral evil
AC 15 (leather armor, shield) | HP 7 (2d6) | Speed 30 ft. | CR 1/4 (50 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 8 (−1) | 14 (+2) | 10 (+0) | 10 (+0) | 8 (−1) | 8 (−1) |
- Skills: Stealth +6
- Senses: darkvision 60 ft., passive Perception 9
- Languages: Common, Goblin
Nimble Escape. The goblin can take the Disengage or Hide action as a bonus action on each of its turns.
Actions
Scimitar. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) slashing damage.
Shortbow. Ranged Weapon Attack: +4 to hit, range 80/320 ft., one target. Hit: 5 (1d6 + 2) piercing damage.
8. Jellyfish Drift
At a glance: levels 2–5 | Navigation / hazard | 15–20 minutes | Creatures: No combat creatures.
Pale bells pulse just beneath the water. Their long threads brush the rescue ladder.
Setup. The anchored ship is 60 feet from a clear southern sandy landing. A 20-foot-wide jellyfish drift surrounds its north side; creatures are an original environmental hazard, not an invented monster stat block.
DM hex map: Jellyfish Drift
Trigger. Entering the marked water exposes a swimmer to the threads.
Run it. Once per turn on entering or starting there, DC 12 Constitution save prevents 1d6 poison damage; success means none. Boathooks push the ladder to the clear south side with one action each. A rowboat carries visitors over the drift without exposure. Waiting 20 minutes lets the current clear it entirely. No paralysis or permanent poison is added.
Resolution and reward. A floating 15 gp tackle box can be hooked from the safe side. Failure costs small damage, not automatic drowning.
Adjust. Easier: drift has a wide clear gap. Harder: the ladder’s fastening needs an action to loosen.
9. Leviathan’s Wake
At a glance: levels 3–6 | Deck hazard | 10–20 minutes | Creatures: No combat creatures.
A ridge of water rises beyond the stern. The shape beneath it is already swimming away.
Setup. The ship has a clear southern heading and visible harbor 200 feet ahead. Three unsecured cargo bundles lie in marked 5-foot deck squares. The distant leviathan is scenery, not a reduced-stat monster encounter.
DM hex map: Leviathan's Wake
Trigger. The lookout’s warning starts a two-round original wake countdown.
Run it. An action secures one bundle with available rope. On count 0 round 2, each unsecured bundle slides 10 feet toward the rail; an adjacent character may use a reaction and DC 12 Strength check to stop it. Failure loses that bundle, not the rescuer. A helm action turning into the wake before it arrives prevents all slides. Tethers protect characters from deck falls.
Resolution and reward. Saving all cargo earns 25 gp from the captain; each lost bundle reduces it by 5 gp, never below zero.
Adjust. Easier: two bundles are already secured. Harder: the helm line is tangled and needs an action to clear.
10. Shipwreck Survivor
At a glance: levels Any | Rescue / social | 15–20 minutes | Creatures: 1 × Commoner.
A hand rises above a plank. Lashed beside it is a waterproof dispatch tube.
Setup. The anchored ship lies in calm water 30 feet from the commoner survivor. A clear southern landing is 100 feet away. No predator or hidden boarding party turns the rescue into a punishment.
DM hex map: Shipwreck Survivor
Trigger. The survivor calls for a rope and says another crew reached the shore.
Run it. A rescue line tossed within 30 feet is caught automatically; securing and hauling it takes one action each. A tethered swimmer can assist without a check. Once aboard, the survivor needs warmth and water, not a mandatory healing spell. They speak Common and identify a safe landing from direct experience.
Resolution and reward. The tube’s named recipient pays 30 gp on delivery. The survivor gives reliable directions to the surviving crew, making any later rescue a concrete lead.
Adjust. Easier: survivor is beside the hull. Longer: a second plank holds a supply bag needed on shore.
SRD reference: Commoner
Medium humanoid (any race), any alignment
AC 10 | HP 4 (1d8) | Speed 30 ft. | CR 0 (10 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 10 (+0) | 10 (+0) | 10 (+0) | 10 (+0) | 10 (+0) | 10 (+0) |
- Senses: passive Perception 10
- Languages: any one language (usually Common)
Actions
Club. Melee Weapon Attack: +2 to hit, reach 5 ft., one target. Hit: 2 (1d4) bludgeoning damage. Commoners include peasants, serfs, slaves, servants, pilgrims, merchants, artisans, and hermits.
11. Maelstrom Madness
At a glance: levels 4–7 | Timed ship hazard | 20–25 minutes | Creatures: No combat creatures.
Foam traces a widening circle around the bow. The harbor markers remain visible to the south.
Setup. The ship lies 150 feet from a safe southern channel. A broad northern whirlpool is original scenario terrain; the ship does not automatically sink on arrival. Anchor, sail, and helm stations are within normal deck movement.
DM hex map: Maelstrom Madness
Trigger. The first circling swell starts initiative and a three-round countdown.
Run it. One action releases the anchor, one trims the sail, and one at the helm makes DC 13 Survival to line up the channel. Failure at the helm can be retried without losing other tasks. Completing all before count 0 round 3 escapes; otherwise the ship circles for 10 minutes, and each unsecured crate takes 1d6 bludgeoning damage. Crew and tethered characters remain aboard; a second task attempt then escapes.
Resolution and reward. Successful coordination preserves cargo worth 40 gp to its owners. A tow line from the southern markers offers a slower 30-minute alternative.
Adjust. Easier: anchor is already raised. Harder: untangle one sail line with an additional action.
12. Sea Gate Sphinx
At a glance: levels 7–10 | Puzzle / social | 15–25 minutes | Creatures: 1 × Gynosphinx.
A winged guardian watches from a dry stone pier. “What can cross the sea without ever getting wet?”
Setup. The ship is anchored 30 feet south of a 60-foot pier, with safe boarding ladders and a north channel gate. One gynosphinx rests at the far end. No swimming speed or aquatic attacks are added.
DM hex map: Sea Gate Sphinx
Trigger. It asks the riddle before permitting the chain gate to be lifted.
Run it. Answers such as a shadow, a spoken message, or a map count if explained. The guardian also accepts 20 minutes repairing the pier’s loose handrail with available rope and wood. Wrong guesses earn hints, not spell attacks or forced aging. Sailing around the pier adds 1 hour and remains possible.
Resolution and reward. Completion earns the safe channel, a 40 gp pearl, and a chart of the next headland. The gate is a site mechanism, not a new sphinx power.
Adjust. Easier: show a ship’s shadow in the water. Longer: help another captain propose a different sound answer.
SRD reference: Gynosphinx
Large monstrosity, lawful neutral
AC 17 (natural armor) | HP 136 (16d10 + 48) | Speed 40 ft., fly 60 ft. | CR 11 (7,200 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 18 (+4) | 15 (+2) | 16 (+3) | 18 (+4) | 18 (+4) | 18 (+4) |
- Skills: Arcana +12, History +12, Perception +8, Religion +8
- Damage Resistances: bludgeoning, piercing, and slashing from nonmagical attacks
- Damage Immunities: psychic
- Condition Immunities: charmed, frightened
- Senses: truesight 120 ft., passive Perception 18
- Languages: Common, Sphinx
Inscrutable. The sphinx is immune to any effect that would sense its emotions or read its thoughts, as well as any divination spell that it refuses. Wisdom (Insight) checks made to ascertain the sphinx’s intentions or sincerity have disadvantage.
Magic Weapons. The sphinx’s weapon attacks are magical.
Spellcasting. The sphinx is a 9th–level spellcaster. Its spellcasting ability is Intelligence (spell save DC 16, +8 to hit with spell attacks). It requires no material components to cast its spells. The sphinx has the following wizard spells prepared: Cantrips (at will): mage hand, minor illusion, prestidigitation 1st level (4 slots): detect magic, identify, shield 2nd level (3 slots): darkness, locate object, suggestion 3rd level (3 slots): dispel magic, remove curse, tongues 4th level (3 slots): banishment, greater invisibility 5th level (1 slot): legend lore
Actions
Multiattack. The sphinx makes two claw attacks.
Claw. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) slashing damage.
Legendary Actions
The sphinx can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. The sphinx regains spent legendary actions at the start of its turn.
Claw Attack. The sphinx makes one claw attack.
Teleport (Costs 2 Actions). The sphinx magically teleports, along with any equipment it is wearing or carrying, up to 120 feet to an unoccupied space it can see.
Cast a Spell (Costs 3 Actions). The sphinx casts a spell from its list of prepared spells, using a spell slot as normal.
13. Sea Hag’s Bargain
At a glance: levels 5–8 | Social / dangerous combat | 20–30 minutes | Creatures: 1 × Sea Hag.
An old figure waits behind a screen of driftwood. A cracked ship’s bell rests between her and the surf.
Setup. The ship anchors 40 feet south of a 50-foot beach. One sea hag remains behind an opaque west screen; the bell stands openly 20 feet inland. North and south departure routes are clear.
DM hex map: Sea Hag's Bargain
Trigger. She asks for the bell’s clapper, visibly trapped under a log, in exchange for a reef chart.
Run it. A lever and two actions free it, or DC 13 Athletics in one action. Keeping the screen in place avoids seeing her true appearance during negotiation. If attacked or deliberately exposed, use actual Horrific Appearance and Death Glare limits, not a blanket bad-luck curse on the whole party. Retreat to the boat is available before revealing her.
Resolution and reward. Return earns a reliable channel chart and 30 gp. Keeping the ordinary bell instead leaves a disputed salvage claim worth 20 gp.
Adjust. Easier: clapper is already loose. Longer: a shipwreck survivor identifies the bell’s original owner.
SRD reference: Sea Hag
Medium fey, chaotic evil
AC 14 (natural armor) | HP 52 (7d8 + 21) | Speed 30 ft., swim 40 ft. | CR 2 (450 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 16 (+3) | 13 (+1) | 16 (+3) | 12 (+1) | 12 (+1) | 13 (+1) |
- Senses: darkvision 60 ft., passive Perception 11
- Languages: Aquan, Common, Giant
Amphibious. The hag can breathe air and water.
Horrific Appearance. Any humanoid that starts its turn within 30 feet of the hag and can see the hag’s true form must make a DC 11 Wisdom saving throw. On a failed save, the creature is frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, with disadvantage if the hag is within line of sight, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the hag’s Horrific Appearance for the next 24 hours. Unless the target is surprised or the revelation of the hag’s true form is sudden, the target can avert its eyes and avoid making the initial saving throw. Until the start of its next turn, a creature that averts its eyes has disadvantage on attack rolls against the hag.
Actions
Claws. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) slashing damage.
Death Glare. The hag targets one frightened creature she can see within 30 feet of her. If the target can see the hag, it must succeed on a DC 11 Wisdom saving throw against this magic or drop to 0 hit points.
Illusory Appearance. The hag covers herself and anything she is wearing or carrying with a magical illusion that makes her look like an ugly creature of her general size and humanoid shape. The effect ends if the hag takes a bonus action to end it or if she dies. The changes wrought by this effect fail to hold up to physical inspection. For example, the hag could appear to have no claws, but someone touching her hand might feel the claws. Otherwise, a creature must take an action to visually inspect the illusion and succeed on a DC 16 Intelligence (Investigation) check to discern that the hag is disguised.
14. Sunken Temple Discovery
At a glance: levels 4–6 | Underwater exploration | 20–30 minutes | Creatures: 2 × Merfolk.
Two swimmers point to a tiled roof visible below the surface. A stone door stands open beneath it.
Setup. The ship anchors above a ruin 10 feet deep, 30 feet south of shore. Two merfolk wait at the ladder. An open 20-by-20-foot chamber, ceiling 8 feet, contains a jammed bronze register; a rope can reach directly back to the ladder.
DM hex map: Sunken Temple Discovery
Trigger. They offer guidance if the party frees the register without breaking its names.
Run it. A lever and two adjacent actions release it; DC 13 Athletics can do it in one. Use normal swimming movement and breath limits; merfolk do not grant water breathing by proximity. The register can be hauled from above once a line is attached. Leaving the ruin is always possible through the open door.
Resolution and reward. Recovery earns a 35 gp pearl and a chart locating the next safe anchorage. No temple-wide curse triggers on entry.
Adjust. Easier: register is loose. Harder: brush silt from its handles with an extra action.
SRD reference: Merfolk
Medium humanoid (merfolk), neutral
AC 11 | HP 11 (2d8 + 2) | Speed 10 ft., swim 40 ft. | CR 1/8 (25 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 10 (+0) | 13 (+1) | 12 (+1) | 11 (+0) | 11 (+0) | 12 (+1) |
- Skills: Perception +2
- Senses: passive Perception 12
- Languages: Aquan, Common
Amphibious. The merfolk can breathe air and water.
Actions
Spear. Melee or Ranged Weapon Attack: +2 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 3 (1d6) piercing damage, or 4 (1d8) piercing damage if used with two hands to make a melee attack.
15. Ship-Devouring Whirlpool
At a glance: levels 5–8 | Hazard / salvage | 20–30 minutes | Creatures: No combat creatures.
A cable catches beneath the bow. Beyond it, a half-sunken mast turns slowly in circling foam.
Setup. The ship is 100 feet south of a wreck lodged beside a visible whirlpool. A southern harbor channel remains open. This original local hazard threatens the snagged cable, not immediate destruction of the whole vessel.
DM hex map: Ship-Devouring Whirlpool
Trigger. The caught cable becomes taut; roll initiative and announce three rounds before it drags the bow against debris.
Run it. Cutting the accessible cable takes an action with an appropriate blade. A character can instead detach its pin with DC 13 Strength as an action, or two actions using a lever. On count 0 round 3 if still attached, one marked bow section strikes debris: DC 13 Dexterity, 2d6 bludgeoning on failure, half on success for creatures there. The cable then snaps and the ship can retreat.
Resolution and reward. Saving the pin permits recovery of a 50 gp salvage crate from the loose cable. Cutting it earns safe escape without that crate.
Adjust. Easier: pin is loose. Harder: move a deck crate to reach the pin.
16. Shore Fey Revelry
At a glance: levels 2–5 | Social | 15–25 minutes | Creatures: 2 × Satyr.
Music carries from a sandbar. Two horned revelers wave a wrapped flute toward your ship.
Setup. The anchored ship lies 30 feet south of a dry 60-foot sandbar with a west landing. Two satyrs stand beside a small ordinary rowboat. Their sea-themed revelry adds no swimming speed or water-breathing trait.
DM hex map: Shore Fey Revelry
Trigger. They request delivery of a named musician’s flute to the next harbor.
Run it. Agreeing earns directions through the visible shoals. They accept conversation, a tune, or a shared ration as hospitality; wine is optional. Refusal leaves the landing open. If threatened they retreat to their boat and row west; no hidden charm forces anyone overboard. Checking the wrapped package reveals only an ordinary instrument and its owner’s mark.
Resolution and reward. Delivering the flute earns 25 gp from musician Dena Orr, named on the wrapping. The satyrs give 2 rations now.
Adjust. Shorter: the owner is waiting at the harbor in sight. Longer: a sailor recognizes the instrument and offers to help perform with it.
SRD reference: Satyr
Medium fey, chaotic neutral
AC 14 (leather armor) | HP 31 (7d8) | Speed 40 ft. | CR 1/2 (100 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 12 (+1) | 16 (+3) | 11 (+0) | 12 (+1) | 10 (+0) | 14 (+2) |
- Skills: Perception +2, Performance +6, Stealth +5
- Senses: passive Perception 12
- Languages: Common, Elvish, Sylvan
Magic Resistance. The satyr has advantage on saving throws against spells and other magical effects.
Actions
Ram. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 6 (2d4 + 1) bludgeoning damage.
Shortsword. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) piercing damage.
Shortbow. Ranged Weapon Attack: +5 to hit, range 80/320 ft., one target. Hit: 6 (1d6 + 3) piercing damage.
17. Shipwrecked Undead
At a glance: levels 4–6 | Combat / remembrance | 20–30 minutes | Creatures: 3 × .
Bones scrape the wreck’s rail. A brass manifest case hangs beside the captain’s empty coat.
Setup. The party’s ship anchors 20 feet south of a grounded 50-foot wreck on a safe sandbar. Three skeletons stand openly aboard; the wreck’s deck is sound. A boarding plank permits normal movement.
DM hex map: Shipwrecked Undead
Trigger. Taking the manifest without acknowledging the crew activates the skeletons.
Run it. Reading the three visible names on the coat’s tags and placing the tags in the case ends their watch, an original peaceful resolution. Otherwise use actual Shortsword and Shortbow attacks. They pursue only aboard the wreck and do not gain swimming speed or underwater bow advantages. Retreat over the plank remains possible.
Resolution and reward. The case contains 45 gp and a log identifying the wreck’s home harbor. Returning the names earns a family contact there.
Adjust. Easier: 2 skeletons. Harder: one name tag is beneath a loose deck board requiring an action to lift.
SRD reference: Skeleton
Medium undead, lawful evil
AC 13 (armor scraps) | HP 13 (2d8 + 4) | Speed 30 ft. | CR 1/4 (50 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 10 (+0) | 14 (+2) | 15 (+2) | 6 (−2) | 8 (−1) | 5 (−3) |
- Damage Vulnerabilities: bludgeoning
- Damage Immunities: poison
- Condition Immunities: exhaustion, poisoned
- Senses: darkvision 60 ft., passive Perception 9
- Languages: understands all languages it knew in life but can’t speak
Actions
Shortsword. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) piercing damage.
Shortbow. Ranged Weapon Attack: +4 to hit, range 80/320 ft., one target. Hit: 5 (1d6 + 2) piercing damage.
18. Aquatic Elemental Disturbance
At a glance: levels 5–8 | Repair / combat | 20–30 minutes | Creatures: 1 × Water Elemental.
Water coils above a submerged gate. Its turning eddy repeatedly strikes the same loosened stone.
Setup. The ship anchors 30 feet south of a stone pier. One water elemental circles a 20-foot pool north; the sluice lever is on dry land 15 feet east. South departure remains clear.
DM hex map: Aquatic Elemental Disturbance
Trigger. Approaching the lever reveals the gate’s missing locking pin in an open toolbox.
Run it. Replacing the pin takes an action and DC 13 Dexterity with tools, or two actions with a simple wedge. Pulling the lever afterward drains the loop, and the elemental moves north into open water. This is original site behavior. In combat use actual Whelm, including capacity, damage, and escape conditions; it does not control the whole sea.
Resolution and reward. Repair earns 60 gp from the harbor authority and opens a safe anchorage. Sailing away leaves a known obstacle rather than a mandatory pursuit.
Adjust. Easier: pin already sits beside its slot. Harder: the lever is on a platform reached by a 10-foot plank.
SRD reference: Water Elemental
Large elemental, neutral
AC 14 (natural armor) | HP 114 (12d10 + 48) | Speed 30 ft., swim 90 ft. | CR 5 (1,800 XP)
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 18 (+4) | 14 (+2) | 18 (+4) | 5 (−3) | 10 (+0) | 8 (−1) |
- Damage Resistances: acid; bludgeoning, piercing, and slashing from nonmagical attacks
- Damage Immunities: poison
- Condition Immunities: exhaustion, grappled, paralyzed, petrified, poisoned, prone, restrained, unconscious
- Senses: darkvision 60 ft., passive Perception 10
- Languages: Aquan
Water Form. The elemental can enter a hostile creature’s space and stop there. It can move through a space as narrow as 1 inch wide without squeezing.
Freeze. If the elemental takes cold damage, it partially freezes; its speed is reduced by 20 feet until the end of its next turn.
Actions
Multiattack. The elemental makes two slam attacks.
Slam. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage.
Whelm (Recharge 4–6). Each creature in the elemental’s space must make a DC 15 Strength saving throw. On a failure, a target takes 13 (2d8 + 4) bludgeoning damage. If it is Large or smaller, it is also grappled (escape DC 14). Until this grapple ends, the target is restrained and unable to breathe unless it can breathe water. If the saving throw is successful, the target is pushed out of the elemental’s space. The elemental can grapple one Large creature or up to two Medium or smaller creatures at one time. At the start of each of the elemental’s turns, each target grappled by it takes 13 (2d8 + 4) bludgeoning damage. A creature within 5 feet of the elemental can pull a creature or object out of it by taking an action to make a DC 14 Strength and succeeding.
19. Deep-Sea Leviathan Warning
At a glance: levels Any | Navigation / decision | 15–25 minutes | Creatures: No combat creatures.
Bubbles rise in a long line beyond the bow. A huge shadow turns far below, away from the shallow headland.
Setup. The ship is 200 feet south of an offshore trench, with a visible western shallow-water route taking 1 hour longer. The distant animal is scenery for an original navigation scene, not an invented abbreviated leviathan fight.
DM hex map: Deep-Sea Leviathan Warning
Trigger. The lookout identifies the disturbance before the ship enters the trench.
Run it. Taking the western route needs no roll. Continuing north requires 10 minutes of depth soundings, with a pole or lead line, to locate a clear eastern edge; a rushed DC 14 Survival check does the same immediately. Failure returns the ship to its last safe heading after 20 minutes, without auto-sinking or unavoidable monster attacks.
Resolution and reward. Careful soundings produce a chart worth 40 gp to the next harbor pilot. A partial chart from the detour is worth 15 gp.
Adjust. Easier: a buoy marks the safe edge. Longer: decide whether to share the new chart with a rival vessel.
Rules sources
Creature references use the 2014-compatible SRD 5.1. See Credits & Licensing for source, license, and adaptation details.