When Power Word, Sleep is cast, the target creature is instantly driven into a comatose slumber.
|“|| Power Word, Sleep|
When a wizard calls upon a Power Word, Sleep spell, he causes a comatose slumber to come upon one creature (other than undead and certain other creatures specifically excluded from the spell's effects). The creature targeted must have less than 20 Hit Points and gets no Saving Throw. Magically sleeping opponents can be attacked with substantial bonuses. The sleep effect will last for 5 rounds. This spell has no effect on creatures with more than 20 Hit Points.