Turritopsis dohrnii, also known as the immortal jellyfish, is a species of small, biologically immortal jellyfish[2][3] found worldwide in temperate to tropic waters. It is one of the few known cases of animals capable of reverting completely to a sexually immature, colonial stage after having reached sexual maturity as a solitary individual. Others include the jellyfish Laodicea undulata[4] and species of the genus Aurelia.[5]

https://en.m.wikipedia.org/wiki/Turritopsis_dohrnii

https://www.bbcearth.com/news/the-jellyfish-that-never-dies

Telomere length shortens with age. Progressive shortening of telomeres leads to senescence, apoptosis, or oncogenic transformation of somatic cells, affecting the health and lifespan of an individual. Shorter telomeres have been associated with increased incidence of diseases and poor survival.

The rate of telomere shortening can be either increased or decreased by specific lifestyle factors. Better choice of diet and activities has great potential to reduce the rate of telomere shortening or at least prevent excessive telomere attrition, leading to delayed onset of age-associated diseases and increased lifespan. This review highlights the role of telomeres in aging and describes the lifestyle factors which may affect telomeres, human health, and aging.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3370421/#:~:text=Telomere%20length%20shortens%20with%20age,of%20diseases%20and%20poor%20survival.