LACKING DEATH. “Turritopsis nutricula is a unique medusa and its transformation potential is unparalleled within the vast array of life-cycle patterns found in cnidarians. This is the first known case of a metazoan being capable of reverting completely to a clonal life stage after having achieved sexual maturity in a solitary stage. Because all T. nutricula medusae regularly underwent transformation, we must assume that organismic death does not occur in this species.”
http://www.biolbull.org/content/190/3/302.full.pdf