Most predators have the decency to kill their victims in the process of feeding on them. Not the cookiecutter shark. Don’t let the cute name fool you, this strange shark species doesn’t get its name from making gingerbread men for its friends, but rather from its tactic swimming up to larger fish, biting into their flesh, and spinning around until a neat little morsel of pain can be popped out. Stay out of the water, everyone.

The perfectly chomped wound on this great white’s head is thought to be the work of a cookiecutter shark species called Isistius brasiliensis which lives off the Pacific coast of Mexico. (Gerardo Del Villar / Pacific Science)

While the cookiecutter shark is no hulking beast of the deep (they are only about the size of a cat), they can leave their victims seriously injured. The biggest scoop the shark has ever taken (that we know of) measured 5 cm across and 7 cm deep. On fish smaller than the great white shown above, the cookie cutter’s mouthful of flesh could presumably be a death blow.

Now for what you’ve all been wondering. Has one of these things ever sampled a person? Unfortunately for anyone who planned on entering the ocean ever again – yes. Such a cruel fate befell Mike Spalding, a regular long distance swimmer who was in the middle of a 33-mile trip between Maui and The Big Island. The bite meant Spaulding had to make a quick retreat to the boat, not wanting his blood to attract the kind of shark that takes more than a morsel.

The shark first tried to cut a succulent medallion out of Mike’s chest, but eventually settled for a leg steak. (Mike Spalding)

Another strange feature of the cookie cutter shark is that it glows in the dark. The fish’s body is covered in photophores that produce a glowing blue coloration that is thought to be used for a most devious purpose. The shark may use its glowing skin to actually attract large predators interested in a midnight snack. When the tuna, marlin, or whale approaches, the fish dodges its jaws, latches onto its flesh and goes to work extracting a meal. This little guy is not afraid of the big boys of the sea, and this extends to subs. The fish has been reported trying to take bites out of the soft domes of nuclear submarines. If you’re still not scared of the cookie cutter shark, at least know that the feeling is mutual.

HT: Florida Museum of Natural History, National Geographic, Wired, Shedd Aquarium