Garlic Glass Snail Oxychilus alliarius
There are a number of Glass Snails. In the Oxychilus genus three species are very common indeed. And all three species look very similar. Empty shells are extremely difficult to tell apart. But maybe you are in luck and you see the inhabitant of the house. In case of the Garlic Glass Snail all you need to do is tickle the animal with a grass halm. Because when irritated the animal smells like garlic or onions. That explains the name. The animal does not actually live in or from garlic. Measuring up to 6 or 7 mm, this species is much smaller than the Dark-bodied Glass Snail. The Garlic Snail is a predator. It will eat almost all other snail, if it is less than some 3 mm. Apparently it does not eat slugs.
