Severed fragments of a sea cucumber kept living and thriving instead of decaying, puzzling researchers.

The discarded fragments of this creature apparently refuse to die, leading researchers to claim immortality

Can Cells from a Sea Cucumber Live Forever?: What scientists are learning about immortality from a humble marine creature

Severed fragments of a sea cucumber kept living and thriving instead of decaying, puzzling researchers.

They seem to reorganize their tissues and then just keep living.