The Bull Demons of Doom 64 are resurrected carcasses of those from Doom 1, resurrected by the Mother Demon. They are made from systematically altered dead carnage remade back into corrupted living tissue. The mutations were devastating. The demons have returned stronger and more vicious than before.
Sorta liked shaved gorillas, except with horns, big heads and lots of teeth. They don't kill easily. Get too close and they'll rip your sorry head off.
Its mutations have given it a bulkier and more menacing appearance, with black horns, smaller red eyes, and accentuated teeth and claws.
Like its earlier counterpart, the Bull Demon has no ranged attack and relies on speed and savagery to kill the player, rushing in zig zag formations and biting. That said it also retains its primary weaknesses, the chainsaw, which will stun-lock the demon and prevent damage to you if you can find a corner or narrow hallway to back into. In larger rooms, the super shotgun is preferred, as Bull Demons are usually found in packs that can flank you if you try to use a chainsaw.