Rammerhead

Rammerheads are hostile mobs that spawn in the Savannah Biome of the Overworld. It is a melee mob that charges at you in order to deal damage. It also has massive knockback. If the Rammerhead misses it's charge, it will circle around and charge again. The Rammerhead is a hunter mob that can only be damaged if the player is at level 12 or higher.

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