Power Word Stun

You utter a single word of power that instantly causes one creature of your choice to become stunned, whether the creature can hear the word or not. The duration of the spell depends on the target's current hit point total. Any creature that currently has 151 or more hit points is unaffected by power word stun. For 50 or less HP, the duration is 4d4 rounds; for 51–100 HP, the duration is 2d4 rounds; for 101–150 HP, the duration is 1d4 rounds.