The spell affects 2d4 undead creatures, plus one undead per caster level, in order of the closest to the thrown material component (see below). No saving throw is allowed to mindless undead, altho the intelligent undead can make saves (at a -2 penalty). The spell affects only corporeal undead; undead (such as vampires) which manage to shift out of corporeal form are freed from the spell's effects.

While performing their dance, undead cannot take any physical actions except the dance itself. The undead suffer a -4 AC penalty, and make physical saving throws only on a 20. Mental capacity is not lost during the spell, so abilities such as psionics and at-will spell-like powers are still usable.

Witnessing this bizarre jig often forces a Horror Check (as per the Ravenloft boxed set) upon the observers. Even the caster is vulnerable to this effect, altho repeated viewing hardens viewers to the spectacle.

The material component for this spell is a skull from a once-undead creature, with jawbone intact. This component is to be tossed, with the spell centered on the skull's landing point. The caster must throw the skull himself, and may possibly miss the intended area (treat the skull as a grenade-like missile). Upon impact, the skull starts wailing a high-pitched cry, doing so for the duration of the spell. The skull's wailing must be audible for the spell to function (the affected undead need not actually be able to hear the wailing, but the sound must be produced). Silence spells or even simply binding the jaw shut blocks the spell's effects, altho the spell will resume if the blockage is removed before the spell's cessation. A Dispel Magic has no effect unless specifically targeted upon the skull. Destroying the skull ends the spell prematurely.