Hybodus (meaning "Humped tooth") was a shark that appeared at the end of the Permian period and died out during Cretaceous period. Hybodus was successful during Triassic, Jurassic, and Cretaceous periods.
Hybodus was about 6.6 feet or 2 metres long and shaped like modern sharks. It had two different kind of teeth in it's mouth and a bony spike on its dorsal fin. It probably used the spike for self-defense.