hitchhiker help
 

I have a new aquarium with new live rock. There is a purplish flower on a couple of the rocks that when i move the magnet cleaner by it, it quickly sucks back into a little ball, virtually disappearing. Can anyone tell me what this is and if it's at all harmful to anything?? Thanks in advance!!

Without a picture its hard to tell. Sounds like it might be a feather duster. Is it connected to a small tube underneath?

i'm an idiot...did a little research and figured out it's a featherduster...sorry for wasting your time