The size of a large dog or pony, pounds the ground to locate burrows
A Giant Pounder Snail is the size of a large dog or pony. It is often heard from a distance, pounding the ground with a hard bony appendage to locate hollows and burrows to break into and then engulf any living matter therein. The appendage is shaped much like a war hammer or mace. Its mouth is little more than rough grinding surfaces, and do little more than 1d2 points of damage, but if provoked they will bite.
Basic Fantasy Field Guide Omnibus