Thank you very much folks, that is the same conclusion I came up with after searching for a while. This rock was purchased from a lfs no names to mention, but all the more reason to qt before introducing to the tank.
I will keep my eyes peeled as the rock is rather isolated in one of the 20g frag tanks in my system.
Do they get much larger than this one, his size was approximately 3/8-7/16"?
Reason I ask is the maturity of the snail and ability to lay eggs.