Hydra

Trembley discovered the hydra, a small primitive organism resembling a plant, but actually an animal. It's tiny tentacles resembled the formidable Hydra destroyed by Hercules. And this hydra could regenerate parts that were cut off, as well as merge with other hydras to become one organism.
 Abraham Trembley Switzerland 1740 Hydra

Trembley discovered the hydra, a small primitive organism resembling a plant, but actually an animal. It's tiny tentacles resembled the formidable Hydra destroyed by Hercules. And this hydra could regenerate parts that were cut off, as well as merge with other hydras to become one organism.