Sarcosuchus

Sarcosuchus is the creature in the nightmares of all kids that lived by the Everglades. It was a gigantic crocodile (not a true crocodile, technically a crocodyliform), but we don't know for certain its size. It was between 33 and 41 feet long, but some experts say that Deinosuchus was larger. This beast lived in the Early Cretaceous, and terrorized large meat eaters.