Craig explains my thinking on the subject of regenerative lizards: "some reptiles will regenerate tails. Specifically some geckos (Leopard gecko being one) will lose tails as a way of getting away from a predator. It does grow back." Pithlord, however, has the goods:
Right, but you don't get a whole new lizard. If you do it right, you can bisect a starfish and get two. Advantage: starfish!