Snail venom

"In 2004, the FDA approved the cone snail venom ziconotide (Prialt) for the treatment of chronic pain. It is only used for severe cases because it must be injected directly into the spinal column. This month, researchers from the University of Utah have reported the discovery of a new snail venom with a completely different amino acid sequence. Because it very selectively attaches to and blocks nerve signals by binding to a particular type of acetylcholine receptor without causing any collateral damage, the newly discovered venom could also become a fantastic medical tool." - Article on Slashdot