ID help.. anemone?

This appears to be spreading in my tank. I Need help identifying this guy. It appears to be out more when lights are off and when the lights come on it shrinks. When I touched it, it would retract but slowly - not nearly as fast as aptasia. It almost looks like a mushroom when the lights are on but when the lights are off it looks more like an anemone with white balls or tips on the end of each tentacle. So any ideas?

Here are some photos of what Im talking about - this is not the same one but looks the same - its just that one was out of the light and easier to photograph. So here it is when contracted:


And here is a similar one that is shaded from the lights and not contracted.

 

Could be a ball anemone. Google it and see.

 

^ Thats what Im leaning towards after searching.. This photo looks VERY similar to what I have. So, next question... good or bad?
Pseudocorynactis caribbeorum - The Free Freshwater and Saltwater Aquarium Encyclopedia Anyone Can Edit - The Aquarium Wiki

 

I'd like to know if its good or bad as well. Cause I have the same type of things in my tank. I have found two and have had them for a couple months now and haven't seemed to do any harm..... yet

 

its a little strawberry anemone

 

is it harmful to anything in particular in a reef tank???

 

I am gonna agree with ball nem. Pretty sure they are good & won't harm anything.