Mobile Bay Reef Keepers

Any ideas on what this might be.. it is about the size of a pencil eraser.
It crawled off of the bright pink frag I got today and went straight onto the clam and on the mantle. I am pretty sure the pink frag was dyed, this thing is the same color , even though the pictures don't show it:

I stuck him in a wine glass until I determine if he is harmless or not.

If you can't tell from the pictures, it looks like half of an oyster shell, and he had two little antenna.

Sorry this was posted in the wrong area, but I believe I have answered my own question. A limpet of sorts, probably a harmless algae grazer.