Coral? Sponge? Pretty rad, either way.
washed up on beach
I've seen this one a lot,generally on docks where the more normal orange version of Botryllus schlosseri is found. Is it possible that this is a later-in-life stage of the same type of tunicate colony?
Ascidiacea (commonly known as the ascidians or sea squirts) is a class in the Tunicata subphylum of sac-like marine invertebrate filter feeders. Ascidians are characterized by a tough outer "tunic" made of the polysaccharide tunicin, as compared to other tunicates which are less rigid.