Polyp stage of Obelia, a hydrozoan (a tiny relative of jellyfish) that can be found as branching colonies attached to surfaces like seaweeds. It uses its tentacles to capture prey. The polyp stage multiplies asexually by budding. Special modified polyps will produce a free-swimming medusa stage that is capable of sexual reproduction.

Observe another species of hydroid.

Part of the Collection of the Other Invertebrates of the Micropolitan Museum © Wim van Egmond