Black Demon (Megajaws)

The Black Demon is a giant shark that is said to live in the waters of Mexico's Baja Peninsula, and terrify local fishermen who cross its path. The question is if it is either a known species, an undiscovered animal, or possibly a living relic of the biggest shark known to man. One possible theory is that it is actually a long dormant species called “Megalodon”, the largest carnivorous shark known to have ever inhabited the Earth’s oceans.

Description
Eyewitnesses describe a massive shark, anywhere from 20-60 feet long, with dark black coloration, and huge eyes. The large beast is most often seen rapidly rising to the surface, before diving just as quickly. Its giant tail whipping wildly as it disappears to the depth of the sea.