Nightmare
Illusion (Phantasm) [Mind-Affecting, Evil]
Level: Brd 5, Sor/Wiz 5
Components: V, S
Casting Time: 10 minutes
Range: Unlimited
Target: One living creature
Duration: Instantaneous
Saving Throw: Will negates
Spell Resistance: Yes
The character sends a hideous and unsettling phantasmal vision to a specific creature whom the character names or otherwise specifically designates. The nightmare prevents restful sleep and causes 1d10 points of damage. The nightmare leaves the subject tired out and unable to regain arcane spells for the next 24 hours.
Dispel evil cast on the subject while the character is casting the spell dispels the nightmare and stuns the character for 10 minutes per caster level of the dispel evil. While the character is stunned, the character can’t act, the character loses any Dexterity bonus to AC, and attackers get a +2 bonus against the character.
If the recipient is awake when the spell begins, the character can choose to cease casting (ending the spell) or enter a trance until the recipient goes to sleep, whereupon the character becomes alert again and completes the casting. If the character is disturbed during the trance, the spell ends.
If the character chooses to enter a trance, the character is not aware of the character's surroundings or the activities around the character while in the trance. The character is defenseless, both physically and mentally, while in the trance. (the character always fails any saving throw, for example.)
Creatures who don’t sleep or dream (such as elves, but not half-elves) are immune to this spell.
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1) Well, he needs to know the target's name so he just can't cast it on anyone.
2) It's a 5th level spell that only causes 1d10 points of damage.
3) Mind Blank would stop it

(sorry, had to throw that in)
4) I think Protection from Evil would block it
Anyway, it's a spell that is a nusiance, but if the character goes and visits a local temple he can probably make it not worth the spellcaster's effort to keep up the assault. Also, if the spellcaster knows the character's name, it is likely that the characters are aware of the caster and could eventually ferret out his location and "permanently" persuade the caster to stop casting the spell
IceBear