Sleep

       Usage: cast 'sleep' <target> : cast 38 <target>
      Effect: Puts your target to sleep 
        Save: Save vs. Magic
        Cost: 24
    Duration: 1 + level/6 hours
Casting Time: 12
      Target: One MOB or character

This spell will fail if the target level is higher than the caster's.  If
you attack a monster you have magically put to sleep, it WILL wake up.

The classes that get the spell sleep are:

magic-user : Level  30 (very good)
bard       : Level  50 (excellent)
darknight  : Level  65 (good)
wizard     : Level  19 (excellent)
illusionist: Level  19 (excellent)
necromancer: Level  65 (excellent)