While giant snakes and terror birds appeared on land after the extinction of the dinosaurs, a group of mammals returned to the sea and evolved into what are now known as whales. Today, we generally think of whales as gentle giants, but for a few million years, whales were anything but gentle.
Livyatan melvillei was a 57 foot (17.5 meter) long ancient relative of the sperm whale that preyed upon 33 foot (10 meter) sharks, dolphins, seals, and other whales. That is decidedly more badass than modern sperms whales, which primarily eat giant squid.
The great whale was named after Herman Melville, author of Moby Dick, the story of a lost ship in search of a legendary predatorial whale.