"The immortal jellyfish has rapidly spread throughout the world in what is being called 'a silent invasion.' The jellyfish has been 'hitchhiking' on cargo ships. Jellyfish have now been observed not only in the Mediterranean but also off the coasts of Panama, Spain, Florida, and Japan."
"The rejuvenation of jellyfish and some other members of the genus is caused by environmental stress or physical assault.
"at any stage of its development — the jellyfish could transform itself back to a polyp, the organism's earliest stage of life, 'thus escaping death and achieving potential immortality.'"
"Plainly speaking, it refused to die. It appeared to age in reverse, growing younger and younger until it reached its earliest stage of development, at which point it began its life cycle anew."