is this a sponge?

[boaconchicken]

I just noticed this guy in my 10 gallon. It retracts when i tap the glass so im not sure if its a sponge or what.

http://img.photobucket.com/albums/v295/boaconchicken/DSC_0222.jpg

[RicksReefs]

tunicate or seasquirt

http://www.reefkeeping.com/issues/2005-03/rs/index.php

[boaconchicken]

thanks for the quick reply

[4218kris]

that awesome i wish i had a seasquirt as a hitchhiker