Power Word Stun

Power Word: Stun

Power Word: Stun (Divination) [Sound-Based]
Level: Mage 6, Assassin 6
Mana: 15. Base Success: 30%.
  Power words are ancient pieces of the sorcerous truespeak from the dawn times of the world. They are inherently unknowable, and creatures who hear one spoken irresistably forget the exact structure of its syllables immediately after hearing it. They can not be recorded, transcribed or preverved by any mortal magic; however, certain powerful divinations can grant a skilled mage knowledge of a Power Word just long enough to speak it once, allowing its terrible effect to take hold on the world.
   This power word scrambles a creature's mind, preventing it from acting coherantly. The victim becomes stunned for a duration that is dependant upon their current hit points -- 1d4 rounds if the victim has 250 or more HP, 3d6 rounds if the victim has 150 to 249 HP, 10d6 rounds if the victim has 149 to 75 HP and a full day if the victim has 74 or fewer HP.