What is this on my zoa plug?!

[Hooz]

I can't say that I've seen anything quite like this before. At first I thought it might be vermetid snail, then I thought maybe aiptasia. Now I'm not sure what to think.

It isn't rigid, and it does seem to be irritating the zoas nearest it a little bit.

Any ideas?!

 

[NashobaTek]

A type of sponge? Try to remove it.

 

[Reefer Drew]

+1 on sponge, Try brushing off with a toothbrush