Hitchhiker ID

[lemonlimesodas]

Hello all what appears to be a ball anemone came with my toadstool.

Any ideas what it is, good/bad.

 

[bradleym]

I'd agree with ball anemone, aka pseudocorynactis.

 

[ISpeakForTheSeas]

Welcome to Reef2Reef!

I think you're right about it being a ball anemone (Corallimorph); they're generally considered neutral from what I've seen. Some species seem to reproduce quickly, but they even then they don't seem to cause any problems.