What happens if you need to catch your own dinner, but you're just not fast enough? If you're a slow-moving cone snail with a yen for sushi, you drug a bunch of fish.

The tropical sluggard kills by overdosing fish with a toxic cloud containing insulin, researchers report this week in the Proceedings of the National Academy of Sciences. Plummeting blood sugar levels throw the victims into a stupor.

Cone snails are notorious for stinging scuba divers tempted to pick up their beautiful shells. But the geographic cone snail (Conus geographus)—the most venomous cone snail of all, with several human deaths under its belt—takes its practice of poisoning to a whole new level.

"It looks like the fish is completely