Bullbos

Bullbos are the boar-like creatures Bulblins ride on in Twilight Princess. After knocking the Bulblins from the Bullbos you can ride the bullbos like you would Epona, except Bullbos can ram structures. The Bullbos are unable to be killed (unless running them off a cliff counts as death-dealing), and are also impossible to stop once provoked (if you ignore the power of stone walls and exhaustion to do just that). In Gerudo Desert, a dead Bullbos is being cooked over a fire. If you destroy it, a Piece of Heart will be revealed.