Aerwhale (The Aether)

Aerwhales are large, floating mobs that occur naturally on any difficulty setting in the Aether. They cannot damage the player, or being damaged, although you can let them bleed with poison darts and set on fire with an flame sword, or be ridden, however they can be pushed. Aerwhales tend to get stuck in the terrain very often, and cannot get out without the player pushing them away. Aerwhales occasionally make deep, high-pitched whale noises. It should also be noted that as of the Aether mod's version 1.01, aerwhales SEEM to be unable to despawn from the Aether once spawned in, unless the player exits through the Aether portal or quits the game. If this is the case, doing either of these periodically is recommended, since the constantly increasing number of aerwhales would eventually "drown out" the spawns of other Aether creatures.