JellyGhast

A ghast that lives underwater, and has the behavior of a jelly fish. Touching its tentacles will shock the player, in which they would take damage and be unable to move for a short while. A JellyGhast would pursue the player, but if it is unsuccessful then it would just give up and do something else. It would drop a JellyGhast tear upon death, which could be used to craft a potion of shock. The player could also recieve the achievement "Shocking" upon killing a JellyGhast.