The aptly named cone snail wears a house that resembles a Ben & Jerry’s receptacle, filled not with ice cream but with a squishy mollusk that sports an extendable, trunklike proboscis. The snails are superficially docile creatures, and can be painfully shy; sometimes they go weeks in a lab without taking a single bite of food, cringing at the slightest change in temperature, lighting, or human supervision. “These are not racing snails,” says Eric Schmidt, a biochemist at the University of Utah.
But when the snails eat, they feast, filling their digestive tract with a glut of battered bodies in various states of drug-induced disarray. Depending on the snail species at hand, some of the corpses might be fish, limp from hypoglycemic shock; they could be worms, sexually stimulated and hot to trot. These poor souls are among the many victims of cone-snail venom—one of the deadliest and most dizzyingly complex substances ever described in an invertebrate.
Some 1,000 species of cone snails exist, each, as far as scientists can tell, with its own unique recipe for venom. Several ingredients seem to closely resemble chemicals naturally made in fish, worms, and other mollusks; in manufacturing them, cone snails can turn their prey’s bodies against themselves. This sort of predatory mimicry is a devious strategy for an otherwise lethargic hunter: If you can’t beat them with speed, narc them and murder them. Had Agatha Christie been a mollusk, she might have been proud.