Bone Carnotaurus is a creature introduced in the Skyward expansion.
While it is not tamable, the player can loot Fossil Blueprints and summon one of them. To do so, the player will need to harvest the File:Fossils.png Fossils listed on the blueprint from File:Fossil Stone.png Fossil Stone cubes located in Burial Grounds biomes. Afterward, the player will need to locate a File:Summoning Alter.png Summoning Alter, which appear randomly throughout the map, and place the blueprint and File:Fossils.png Fossils in it. After a lengthy summoning process, the player can tame the Bone Carnotaurus in the the same way as a normal Carnotaurus.
Once summoned and tamed, the Bone Carnotaurus will need 
Void Energy in order to run or fly.
Yes, you read it right. They can fly! While they cannot strafe they can fly both forward and backward for as long as you keep their Void Energy pool charged. They can also sprint in both directions while in flight.