Spelltrap (from the Book of Eldritch Might) Abjuration
Level:Sorcerer/Wizard 4 Components: V, S, F Casting Time: 1 full round Range: Touch Target, Effect, or Area: One gem
Duration: 1 minute per caster level
Saving Throw: None (see text) Spell Resistance: Yes (object)
Spelltrap imbues a gem with the power to absorb a spell then release its energy. The gem becomes invisible and incorporeal and is tied to a specific creature, object, or 10-foot-cude of space, designated by you. If associated with a creature or object, the gem moves when the creature or object moves, always remaining within 1 foot.
The gem stays dormant until someone casts a particular spell (or any level) which you specified earlier, on the creature, object, or area. At this time, the gem activates, absorbing the spell and becoming visible and tangible. An active gem no longer moves, even if it had been tied to a moving creature or object. If anything or anyone touches the gem after it has become active, it explodes, inflicting 2d6 points of damage for each level of the spell it absorbed to all within a 20-foot spread. Those in the affected area may make a Reflex save for half damage.