What is this!!! bubble kind

[osmaven]

Please help!

Can any one tell me what is this?
It is like a cristal bubble, it has double its size in the past two months. should I remove it or leave it alone?

 

[saltycreefer]

Valonia. It is a nuisance algae. I would leave it though if theres just the one. They grow really big, but if it starts to multiply, you can get some emerald crabs to take care of them.

 

[osmaven]

I have a couple of emerald crabs but they have not touche it. Let me ask you, this will burst? what should I spect?