A dragonfly larva needs a mask in order to eat. The mask is the lower jaw that can be pushed outward. When the dragonfly is resting, the jaw covers a lot of the face, just like a mask. The larva lives in water and preys on insects, small fish, and tadpoles. The mask is hinged, and can be shot out suddenly. Two hooks on the end stab the prey, so it can be pulled back into the mouth.