If it has a shell, it is a snail. Snails will eat foliage, but I don't think lawns are their 'thing'. The only time I've even seen terrestrial snails in my zone (6) have been escapees from the g'house. I'm assuming we have them, though. Slugs are the major slimy culprit in our area.

Slug or snail, cousins. They both need a moist, cool environment and most usually do not move far from shady shelter. If there are large numbers one means of control is Iron Phosphate sold as Sluggo or Escargo.

It's a snail. Don't know which one.

As has been said, they eat plants other than lawns.

For some reason the snails with this shell shape have come in herds in my plantings. They will be all sizes from pinpoint to about 1 inch. They do squish easily.

Off topic, FYI, for several years I have been seeing fewer of the regular snails whose shells pinwheel from the center in a tight spiral. Having seen so few I was surprised to find two in a glass of beer I left out for the slugs. No need for any response I just thought I would comment on the lack of what I call real snails in my area. I have not had toads for about 5 years also.