anemone id help please people

[skian2hott]

hi every one i added a small piece of live rock i got from a friend and a day later i noticed this little guy hanging about i would like to id him asap cause i dont have enough light power yet so if hes not a pest i can get him back into the tank he came from to keep him alive till i get my lights

 

[mayjong]

ball anenome. how big is it?
typicall hitchhiker

 

[squishifishi]

+1
that is what my white ball corallimorph looks like. they are generaly harmless. They prefer lowlight/shaded areas as they are non-photosynthetic and will open up nicely under these condition.
how big is it though?