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.

 

[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