Say you’re looking to make the next generation of medical tape. You want something that will hold skin and other organs together while they heal. You want it to be more convenient than sutures and less brutal than staples. It has to stick easily, hold on tightly, and come off painlessly.

There are worse places to search for inspiration than the guts of a fish.

Fish intestines are home to a group of parasites called spiny-headed worms, or acanthocephalans. Their most distinctive feature is a spine-covered snout that the worm stabs into the gut walls of its host. Once inside, it contracts two muscles and the long snout rapidly swells into a bulb, anchoring the worm in place. The fastened parasite