Bubble algae?

[Mikek]

Ok, so this green thing in the center of the pic, is this bubble algae? A scallop or clam? or some kind of other algae or critter? I do have one scallop in the tank that hitchhiked on some coral rockbase, but I don't have a good enough view of that one to compare it to this.
Thanks in advance for the responses :D

 

[ErinCahir]

It's not bubble algae...

 

[Mikek]

Whew! I didn't think so, as that seems to grow in bunches and seems more transparent, but figured I'd throw it at the experts here to confirm :)

 

[Aquarian]

It's a bivalve nice hitchhiker. LionfishLair.com - Hitchhiker Guide to your Aquarium