Some prey may develop an immunity to some toxins, or maybe new prey replaces the creatures that the snails had been dining on. As a result, Conus snails have developed a versatile warehouse of toxins that can work in many different ways on different types of prey. Most look no more deadly than your ordinary garden snail. It's their lifestyle that sets them apart. They hide under rocks or coral rubble during the day, and then at night they emerge and they begin to hunt.
Some species only eat fish, some only eat other snails, and most eat worms.
Adults range in size from about one inch long to up to 10 inches. Most of the fish eaters are about 4 to 5 inches in length. The deadly end of the snail is a proboscis that extends from its mouth like a hypodermic needle. At the end of it is a little harpoon-like tooth with barbs. The snail rubs its proboscis along the side of the victim until it finds just the right spot, and then sinks in its tooth and injects the venom.