The mobs of the upcoming Dark Moon Event exist in the files of the 2.5 Snapshot, but almost nothing is known about them. They can be seen below. It has been suggested that the mobs of Dark Moon will drop the realmstone to Playtopia, but nothing is confirmed. It is unknown what version these will be added in, but if the Playtopia theory is correct, then they will most likely be added in 2.7. Note that these are subject to change.