Most squid snatch their prey with a pair of extendable tentacles, which can shoot out at high speed. These muscular limbs are longer than the other eight arms, and end in a bulbous “club” that’s covered in suckers or hooks. Once they latch onto something, they rapidly contract and bring the prey in towards the squid’s sharp beak.

But one deep-sea squid—Grimalditeuthis bonplandi—is very different. Its tentacles are thin and fragile, and almost always break off when it’s captured. For ages, people thought it lacked tentacles altogether until a full specimen was found in the stomach of a fish. Weirder still, its clubs have neither suckers nor hooks. Instead, they are flanked by a pair of leaf-shaped membranes. Why?

Now, after