The fishermen knew. They told stories of swordfish using their eponymous swords to stab sharks and other large fish and mammals. Scientists, however, were skeptical.  Recently, however, more than six dead sharks have washed up around the Mediterranean, all apparently stabbed, usually in the head, by swordfish.

The first victim, a blue shark, washed ashore in Valencia, Spain in 2016 with a fragment of a swordfish sword embedded in its brain. The NYTimes reports: 

But since then at least six more sharks have washed up on Mediterranean coasts, each impaled with the same murder weapon, and almost always in the head. In the latest example, an adult 15-foot thresher shark — itself equipped with a whiplike tail capable of stunning blows — washed up in Libya. Inside was a foot of swordfish sword that had broken off near its heart….

When sharks die, their bodies typically sink to the bottom of the sea. So a published record of half a dozen stranded sharks with suspiciously precise wounds could indicate that these encounters are common — and that a swordfish sword is sometimes exactly what it sounds like.

Some species of sharks are known to eat young swordfish, so it is possible that the attacks could be defensive. It is also possible that the attacks are conflicts between two apex predators competing for food or territory.

While rare, swordfish have been known to attack humans. In 2016, off the coast of Brazil, a commercial diver was attacked by a swordfish. Fortunately, the sword struck the diver’s air tank rather than the diver’s neck or back, and the sword became tangled in the diver’s gear. A video taken by a fellow diver captures the attack.