Imprison Possessor

The caster traps one creature that can possess or inhabit other creatures, or one that can move its mind out of its body, within the creature it currently inhabits.

Book of Vile Darkness 3.5
By Monte Cook

Abjuration
Level: Sorcerer/Wizard 5
Components: V, S
Casting Time: 1 action
Range: Close (25 ft. + 5 ft./2 levels)
Target: One possessing creature and its host
Duration: Permanent (D)
Saving Throw: Will negates
Spell Resistance: Yes

Potential targets include possessing demons, malevolent ghosts, and a caster currently using a magic jar spell. The possessing creature cannot leave the body it is currently in, whether or not it is its own, by any means.