The Sand dollar is well named - it looks like a coin after all. However, this denizen of the Pacific coast has a trick up its sleeve. It can clone itself.
Bizarre, but true. A few years ago scientists discovered that the larvae of the Sand dollar are able to clone themselves. When they were exposed to the mucus of their natural enemies – fish – they demonstrated a unique defense mechanism. They cloned themselves which meant more or less that they halved their size. It is thought that this new smaller size helps them to avoid detection by fish and so increase their survival chances.
From the Upcoming ueue, submitted by taliesyn30.
The second summer after we had moved there from New York, we started finding live ones while wading. We collected over 100. Never really saw a lot of them after that summer. Maybe we shouldn't have taken those.
It beats the hell out of this - they clone themselves en masse from their polyp stage (which can never end, causing many many clones to be released for as long as the polyp is living).
http://animals.about.com/od/cnidarians/a/lifecyclejellyf.htm