ID this thing

[azcummins]

Can anyone tell me what this bubble looking thing is? It looks like a piece of coral with a transparent membrane surrounding it. I can't figure out what it might be.

 

[fugupuff]

Can anyone tell me what this bubble looking thing is? It looks like a piece of coral with a transparent membrane surrounding it. I can't figure out what it might be.

sea squirt, tunicate, there are many different species. google it, and you can read about the basics on wikipedia!

 

[Reefscape]

Just normal sponges....they will grow and recede, depending on nutrient levels...