Green and white spiral..snail?

[Budman93]

I noticed vermitid snails earlier and started taking out and scraping every piece of live rock i have. (Just put it in yesterday so its still new) i also noticed this massive critter jammed in the middle of my LR. I thought it might be a giant Vermitid but this thing looks much bigger and is a different color. Any ideas? Good? Bad? You guys are life savers!

 

[MasterBacon]

Can't tell, looks like a clam shell to me.

 

[ELwirePros]

It could be the following form a Turbo Snail. These seem to hang around in my tank from time to time after they die.

The operculum, meaning little lid, (plural: opercula or operculums) is a corneous or calcareous anatomical structure like a trapdoor which exists in many (but not all) groups of sea snails and freshwater snails, and also in a few groups of land snails. In other words, this structure is found in some marine and freshwater gastropods, and in a minority of terrestrial gastropods, including the families Helicinidae, Cyclophoridae, Aciculidae, Maizaniidae,Pomatiidae, etc.

The operculum is attached to the upper surface of the foot and in its most complete state, it serves as a sort of "trapdoor" to close the aperture of the shell when the soft parts of the animal are retracted.

 

[ELwirePros]

This part...

 

[ahiggins]

I agree with EL, it does look like that.
My other thought is a bivalve of some sort.

 

[Budman93]

This part...

That looks exactly like it and when i gently shook the rock it fell further in so maybe its's just dead organic matter from a previous snail. Should i bother getting it out? I just started my cycle. So i dont know if theres a point. Also on a side note a baby serpent star fell out of the liverock when i put it back in the tank! I know they get huge but I think itd be fine to keep for awhile since it was barely an inch long.