The winner of today’s photography challenge is the snail that was moving around the pond about a month or so ago. Snails belong to the class Gastropoda (and there are more than 65,000 species within the class) within the phylum Mollusca. This class is the largest group in the phylum, and includes both snails (land, fresh & sea) and slugs (both terrestrial and sea).

This is a land snail, and they can go dormant during unfavorable weather conditions (cold, heat, drought).

As with any animal, depending on where they are originally from (and then introduced), they can either become somewhat beneficial or harmful. Take the snails of Hawaii—over half are extinct (thanks to destruction of habitats, unintentional introduction of rats and non-native snails, and shell collection), and of the remaining species, most are critically endangered.
There are a small handful that cause health issues (only because they’re intermediate hosts for other parasites); for example there are several snail & slug species that serve as intermediate hosts for the rat lungworm—which can migrate to the brain and cause moderate to severe damage once it encysts within the brain tissue. Schistosomiasis is another disease that is caused by minute blood flukes that have snails and/or slugs as intermediate hosts.
They aren’t all bad though—they do have an important role to play in the ecosystem—they’re decomposers. They will help break down dead plant and animal matter into nutrients and compounds that living plants can uptake through their roots. Other snails are predators, and help keep other insect/snail/slug populations in check as well.

Then there as the time I did a little gardening work in the early spring, and when I turned over one of the rocks–I found a good number of snails attached to the bottom of it.

So I try to make sure that they get into the garden, or the compost pile to help break down all the dead leaves and other things that have been accumulating all winter. It will be interesting to see if I get out into the gardens this fall if I will find any snails or not.
Reference: https://www.britannica.com/animal/gastropod