Disbelieving Illusions

Parent page Illusion

Sometimes illusions allow an affected creature a chance to disbelieve the spell, which lets the creature effectively ignore the spell if it succeeds at doing so. This usually happens when a creature Seeks or otherwise spends actions to engage with the illusion, comparing the result of its Perception check (or another check or saving throw, at the GM’s discretion) to the caster’s spell DC. Mental illusions typically provide rules in the spell’s description for disbelieving the effect (often allowing the affected creature to attempt a Will save).

If the illusion is visual, and a creature interacts with the illusion in a way that would prove it is not what it seems, the creature might know that an illusion is present, but it still can’t ignore the illusion without successfully disbelieving it.