Chimera

Chimeras are hostile mobs that spawn in the Savannah Biome of the Overworld. It is a melee mob that lowers the amount of melee damage you deal when it hurts you. This effect does not stack. The Chimera is a hunter mob that can only be damaged if the player is at level 12 or higher.

References/Sources
http://adventofascension.gamepedia.com/Chimera