Shadow trap

Shadow trap was a conjuration spell that placed a magical trap on any item or object that was capable of casting a shadow. A greater shadow was bound to this trap and was released at the moment the trap was sprung.

Effects
When the affected object was moved or altered in a way that shifted its shadow, the shade creature emerged from the shadow that was naturally cast by the object. It functioned as any other specimen of the incorporeal undead would, and attacked the first person or being it encountered. It remained on the Prime Material plane for a matter of seconds, depending on the skill and experience of the caster.

If the spell was cast upon an item that cast no shadow, the spell's effects would not trigger though it would remain in effect. The effects could be triggered by any action that altered the object's shadow such as moving or otherwise altering a nearby light source.

Casting
In addition to verbal and somatic components, the casting of shadow trap required a sheet of black cloth of sufficient size to cover the trapped object.