Carcharias megalodon! This fearsome shark swam the seas of our planet during the Cenozoic Era eating anything and everything in it's path, including whales. Usually referred to as a megalodon, and sometimes by the endearing nickname, "Meg", this beast, which could be 45 feet or longer full grown, is supposedly extinct.
The arguments persists. Eye witness accounts remain in the literature and Shark Week, 2013, opened their shark-a-palooza with a 2 special about the Meg as their first show.