From Site:
"Turritopsis nutricula is a hydrozoan, and it’s considered by scientists to be the only animal that cheated death.
"Hydrozoa are a huge class of predatory animals that live mostly in saltwater, closely related to jellyfish and corals. Eggs and sperm from an adult jellyfish (medusa) and they then develop into polyp stage. Medusae evolve asexually from polyps.
"What these little folks do is they revert completely to a sexually immature, colonial stage after they reach sexual maturity."
"They’re able to return to polyp stage due to a cell change in the external screen (Exumbrella), which allows them to bypass death. As far as scientists have been able to find out, this change renders the hydrozoa virtually immortal."
[via: http://www.zmescience.com]
http://www.sciencenews.org
