The skull affected by this spell speaks its message the next time a specified event occurs. When the skull's magic is triggered, it releases wild and unnerving cackles before speaking its message. All creatures that can hear the cackles must save or become shaken for 1d4 rounds. The message, which must be 25 or fewer words long, can be in any language known by you and can be delivered over a period of 10 minutes. The mouth cannot utter verbal components, use command words, or activate magical effects. It does, however, move according to the words articulated; the mouth of the skeleton moves and appears to speak.

The spell functions when specific conditions are fulfilled according to your command as set in the spell. Commands can be as general or as detailed as desired, although only visual and audible triggers can be used. Triggers react to what appears to be the case. Disguises and illusions can fool them. Normal darkness does not defeat a visual trigger, but magical darkness or invisibility does. Silent movement or magical silence defeats audible triggers. Audible triggers can be keyed to general types of noises or to a specific noise or spoken word. Actions can serve as triggers if they are visible or audible. A cackling skull cannot distinguish alignment, level, Hit Dice, or class except by external garb.

The range limit of a trigger is 15 feet per caster level, so a 6th-level caster can command a cackling skull to respond to triggers as far as 90 feet away. Regardless of range, the mouth can respond only to visible or audible triggers and actions in line of sight or within hearing distance.

Cackling skull can be made permanent with a permanency spell.