What are these white powder puffs?

[lakwriter]

My tank is only a few months old. In the last 2 weeks, I have discovered several little white powder puff balls on some of my rocks. They are tiny and look like a round puff of cotton. What are these? Should I remove them?

[Amphiprion]

Any pictures? Could be any number of things, from sponges to water molds.

[serpentman]

They are most likely tunicates and are completely harmless. Do they look like this?

http://www.melevsreef.com/id/tbs/scypha_tb.jpg

[lakwriter]

Yes, Thats what they look like. If I wanted to get rid of them (if they become a problem (I only about 4 now), how would I do that? Can I pick them off with tweezers?