Rhinosaurus was a creature that was enslaved by Maximillian Spiel, and forced to fight in a mutation arena. Rhinosaurus was pitted agains Godzilla, after Spiel kidnapped him. The two fought, and eventually Spiel forced Niko Tatopoulos and Elsie Chapman into the ring as well. Rhinosaurus held his own in combat, and soon Spiel released the Giant Water Beetle and started firing upon Godzilla with energy beams to blind it and give Rhinosaurus the advantage. Mendel Craven destroyed the beam emitter, allowing Godzilla to properly fight. As Rhinosaurus charged, and Godzilla knocked him off balance and defeated him.
The Rhinosaurus did not posses any special abilities, for it was merely a titanic rhinoceros. However, the Rhinosaurus was still a force to be reckoned with, being equipped with thick, durable hide and a massive horn.
- The Rhinosaurus is speculated by some to be the American counterpart to Baragon.