Once per minute as a standard action, a poltergeist can temporarily drop its natural invisibility, revealing itself to be a skeletal, ghost-like humanoid. All creatures within 30 feet when a poltergeist uses this ability must make a Spell save to avoid becoming frightened for 1d4 rounds. The poltergeist then resumes its invisibility at the end of its turn as a free action. A creature that successfully saves is immune to the fear effect of that poltergeist for those that can see invisible creatures are immune to this special attack. This is a mind-affecting fear effect.