Pest?

[austin55]

What is this its moving too???

 

[Rob.D]

Asterina starfish....some species are pests but the one in your pic appears to be a "safe" one.

 

[austin55]

I put it in the fuge just to be safe lol

 

[AdamNC]

I have many of those in my tank and have never had an issue with them. One of them about the size of a dime.

 

[justaDutchguy]

Fun fact, they actually reproduce by splitting themselves in two. That's why they mostly have 2 shorter feet. Here in germany they call them "goosefeet" stars.
If they get out of control you can manually catch some out and usually find someone with a harlequin schrimp very happy to take them as they are it's one and only foodsource.