Eucheilota bakeri

Eucheilota bakeri, the bean clam hydroid, is a species of hydroid in the family Lovenellidae, occurring in the Eastern Pacific: USA and Canada.
The life cycle includes both asexual and sexual stages; the species is capable of reproduction in both stages. Asexual reproduction occurs by a process called budding; this form of the animal is called a hydroid. Sexual reproduction occurs with the release of gametes by the adult form called a medusa.
Hydroids are often found attached to the shell of a Gould beanclam.