"Krika triggered his mask power. The Kanohi Crast, or Mask of Repulsion, sent Gorast hurtling away from him at high speed. She smashed into a nearby stalactite with a sickening thud and hit the mud, dazed."
The KanohiCrast is the Mask of Repulsion. It allows its' user to repel other objects for offense or defense; the target cannot touch the user, and is flung away with considerable force. The user can also achieve limited flight by repelling the ground.