orange sponge?

[ascvet]

I have this orange stuff growing on a rock. It looks like little chains or cirlces lined up in double rows. Any idea what this is?

 

[small alien]

howzabout a pic?

 

[dendro982]

Chains in double rows could be colonial turnicates, although mine were less colorful.

 

[PSLee]

Try passing your hand over the colony. If it contracts they are most likely colonial tunicates. And if they consist of "little chains or circles lined up in double rows", then they are very likely to be Botrylloides sp.