Phantasmal Force 5e: Investigation, Damage, and Limits

I like Phantasmal Force because it creates a problem inside one creature’s mind rather than placing an image in the shared world. That makes the illusion unusually convincing to its target, but it does not give the caster permission to add conditions or physical restraints the spell never names.

The main guidance below uses the 2014 spell. The SRD 5.2.1 table presents the revised version, including its higher damage.

Phantasmal Force 5e — Quick Spell Reference

SRD note: Phantasmal Force is not included in SRD 5.1, so this table uses SRD 5.2.1. The main guide identifies the revised damage separately from the 2014 spell.

How Phantasmal Force Works in the 2014 Rules

Choose one creature you can see within 60 feet. The target makes an Intelligence saving throw. On a failed save, you create a phantasmal object, creature, or phenomenon no larger than a 10-foot cube. Only the target perceives it, including the sound, temperature, and other sensory details appropriate to the phantasm.

On a successful save, nothing happens. On a failed save, there is no automatic repeat save at the end of each turn. Instead, the target can spend its action examining the illusion and make an Intelligence (Investigation) check against the caster’s spell save DC. Success reveals the illusion and ends the spell.

The spell requires concentration for up to 1 minute. Losing concentration ends the phantasm immediately.

The Target Rationalizes Impossible Results

An affected creature treats the phantasm as real and explains away contradictions while the spell lasts. If a phantasmal bridge fails to support its weight, for example, the target might believe it slipped, was pushed, or encountered a damaged section rather than concluding automatically that the bridge is unreal.

Rationalization is not unlimited control. The caster does not choose the target’s actions, beliefs beyond the illusion, or exact explanation for every event. The target retains its personality, goals, movement, and actions. The DM decides how it responds to the perceived phenomenon using the spell’s instruction that it treats the phantasm as real.

Other creatures do not see or hear the phantasm. They can observe the target’s reactions and try to communicate, but a warning from an ally does not automatically end the spell. The stated way for the target to disbelieve it is the Investigation check, while loss of concentration or the duration ending also removes it.

What Can Fit Inside the 10-Foot Cube?

The phantasm can depict one object, creature, or other phenomenon no larger than a 10-foot cube. A compact monster, cage, fire, pool of acid, wall section, or broken bridge segment can fit. The size limit prevents the spell from creating an entire castle, battlefield, or landscape.

The image exists only for the target, so it cannot provide real cover, bear weight, block a doorway for other creatures, carry an object, or physically restrain anyone. Physical interaction can produce an impossible result, but the affected creature rationalizes that result rather than automatically ending the spell.

Does Phantasmal Force Cause Blinded or Restrained?

No condition is imposed automatically. Creating a phantasmal hood, cage, chain, or wall does not by itself give the target the Blinded or Restrained condition. Those conditions have defined mechanical effects, and Phantasmal Force does not state that it applies them.

The illusion can still influence what the target believes it can see or where it thinks it can move. Exactly how that belief changes the target’s decisions is DM adjudication, not a hidden condition supplied by the spell. A fair ruling should respect both halves of the spell: the target treats the illusion as real, but the illusion has no physical substance and grants no listed condition.

Psychic Damage from a Dangerous Phantasm

Under the 2014 rules, a phantasm that represents a dangerous creature or hazard can deal 1d6 Psychic damage to the target once each round on the caster’s turn. The target must be within the phantasm’s area or within 5 feet of it.

The target experiences that Psychic damage as a type appropriate to the illusion, such as fire from a phantasmal flame. Mechanically, however, the damage is Psychic. Resistance or immunity to the imagined damage type does not change that unless another rule says it affects Psychic damage.

The damage requires an appropriate dangerous phantasm. A harmless chair or ordinary book does not become damaging merely because the caster wants the extra die. The spell does not gain damage from a higher-level slot.

Phantasmal Force: 2014 vs. 2024 Rules

The largest revision is damage. The 2014 spell deals 1d6 Psychic damage once each round on the caster’s turn when its hazard requirements are met. SRD 5.2.1 raises this to 2d8 Psychic damage on each of the caster’s turns.

The revised rules name the target’s examination a Study action, followed by the same Intelligence (Investigation) check against the spell save DC. The Intelligence save, 60-foot range, 10-foot-cube limit, concentration, rationalization, and one-target structure remain substantially the same.

Because the quick-reference table uses SRD 5.2.1, its 2d8 value must not be imported into a strict 2014 game.

Phantasmal Force FAQ

Can another creature see the illusion?

No. Only the target perceives the phantasm.

Does the target repeat its saving throw every round?

No. After failing the initial save, it must spend an action and succeed on the stated Investigation check to discover the illusion.

Can Phantasmal Force physically trap a creature?

No. The phantasm has no physical substance and does not automatically impose Restrained or another condition.

Can the spell deal a damage type other than Psychic?

No. The target may perceive a thematically appropriate damage type, but the actual damage is Psychic.

Rules sources: Player’s Handbook (2014), p. 264; the revised Phantasmal Force spell; and SRD 5.2.1. Illusion behavior beyond the explicit mechanics is identified as DM adjudication.