Mushroom coral(?) identification

[bigcoral]

This little guy came in off of a live rock & I can't help but think it's a mushroom coral.. Anyone think they know what type? Sorry for picture quality but this thing is tiny!

 

[Sump Crab]

Looks like a nice blue disco

 

[Larry isaak]

It’s just a simple green discosoma mushroom it should get slightly brighter as it grows.