A favorite among shell collectors, the diminutive cone snail--larger specimens grow to be about 23 centimeters in length--is as renowned for its beautiful shell as it is for its potent venom. The majority of cone snails are found in warm, tropical waters.

Their appearance notwithstanding, cone snails are fearsome predators that immobilize their prey with a poison-tipped radula, a tooth-like ribbon made out of hard chitin that can be launched with the force of a spear. Their venom, which paralyzes their prey almost instantly, contains neurotoxins that target specific nerve receptors, or channels.

Though these toxins can be lethal when injected, scientists have been extracting the compounds to create pain-relieving drugs. In 2004, the first painkiller derived from the toxin of the species Conus magus, called Prialt, was approved for use in the United States and Europe. The drug helps relieve chronic pain in patients who no longer respond to morphine. Applied directly to the spine, Prialt (generic name: ziconotide) acts by selectively blocking calcium channels in the brain, preventing the release of neurotransmitters that cause the sensation of pain.