Cookiecutter Shark Isistius brasiliensis
Many cetaceans and large fish, including other sharks, suffer when cookiecutter sharks are around. This small, cigar-shaped shark is a parasite that bites chunks out of its prey. Using its unique thick, flexible lips to hold onto its victim by suction, it then twists itself around so that its razor-sharp lower teeth bite out a cookie-shaped piece of flesh. The cookiecutter shark is active at night, luring its victims with glowing green bioluminescent lights on its belly. It also preys on squid and crustaceans.