Identification please

[Perdy]

This little thing has slowly been growing on my live rock. It closes up at night.
Have I been lucky and got a nice little hitchhiker or is it nasty?

 

[Rscomia]

Are you talking about the thing right in the middle?

 

[0o.Kelsey.o0]

Looks like a button polyp if that's what you are talking about Good hitchhiker.

 

[Sarcothelia]

Some sort of Zoanthid/Palythoa. Good find

 

[Rscomia]

I have what looks loike the same thing as a hitchiker and the closest thing I could find that looks like it was a seamat polyp

 

[melosu58]

I agree. Button polyp.