Nearly Immortal Sea Creature

Small but pervasive, this jellyfish-like hydrozoan (Turritopsis dohrnii) takes several forms. It can survive tough times by collapsing into a blob and then growing back into its youthful, stalklike form. Turritopsis often don't die. They just get young again.

Normally the organisms reproduce like grown-ups with sperm and eggs. In case of emergency, though, a bedeviled bell sinks down and the blob of tissue sticks to a surface below. There Turritopsis’ cells seem to reverse their life stage. When the blob grows again, it becomes the stalklike polyp of its youth and matures into a free-floating bell all over again. LINK