To move that giant body through the water, it had powerful, 10-foot-long paddles. The scientists say the beast also had cucumber-sized teeth made for chomping, so it probably didn't spend its time peacefully cruising the ocean in search of little snacks of plankton and krill. Instead, it most likely went after large fish and even other swimming beasts, such as ichthyosaurs. Scared of sharks? Just be glad these things aren't still cruising the oceans.