A tiny animal called Hydra doesnt age

Hydra is a genus of simple fresh-water animals possessing radial symmetry. Hydras are predatory animals belonging to the phylum Cnidaria and the class Hydrozoa. They can be found in most unpolluted freshwater ponds, lakes and streams in the temperate and tropical regions by gently sweeping a collecting net through weedy areas. They are usually a few millimeters long and are best studied with a microscope. Biologists are especially interested in hydras due to their regenerative ability and because they appear to undergo senescence (aging) very slowly, if at all.

http://en.wikipedia.org/wiki/Hydra_(genus)

http://en.wikipedia.org/wiki/Biological_immortality#Hydra