Small anenome or coral or something else.

[Rybo]

Don't know what it is but I took a couple pics one open one closed. Small circular with white dots at end of small tentacle like structures. Seems to not like light as it closes when I turn lights on

 

[mr_X]

It's a corynactis. Harmless.
Corynactis californica - Wikipedia, the free encyclopedia
They never amount to anything in closed systems.

 

[Rybo]

Thank you that is exactly what it is