I found this guy on the side of a hammer frags base that I purchased, it was on the base not the plug. I tried removing it by getting my fingernail under the edge and pullung, but it would not come off, even with abive moderate pulling with my finger nail. I thought it may be part of the hammers base and I didn't want to hurt the hammer, so I left it on. Now its on my rock. Its a hard shelled animal like a flat snail or something. Anyone know what this is, and if they are benificial or harmfull ? Could it be a baby turban snail?