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Call Nightmare

(Book of Vile Darkness)

Conjuration (Calling) [Evil]
Level: Demonologist 4, Sorcerer 5, Wizard 5,
Components: V, S, Soul
Casting Time: 1 minute
Range: Medium (100 ft. + 10 ft./level)
Effect: One nightmare
Duration: One week
Saving Throw: None
Spell Resistance: No

The caster calls a nightmare from the Lower Planes to where she is, offering it the soul that she has prepared.
In exchange, the nightmare serves the caster for one week as a mount or guard, although if the nightmare moves more than 150 feet away from her, it immediately returns whence it came.
Multiple castings of this spell replace the previous nightmare with a new one.