polyp

noun

1. medicineAn abnormal growth protruding from a mucous membrane.

2. zoologyA cylindrical coelenterate, such as the hydra, having a mouth surrounded with tentacles.

3. One of two forms that coelenterates take (e.g. a hydra or coral): usually sedentary with a hollow cylindrical body usually with a ring of tentacles around the mouthanimal

   “in some species of coelenterate, polyps are a phase in the life cycle that alternates with a medusoid phase”