This little guy is a milk snail (Otala lactea). The shell colors of milk snails can be highly variable, but they are usually shades of brown. They are nocturnal herbivores. They are an invasive species, thought to have been introduced to Florida in the early 1900’s from the eastern Mediterranean or northern Africa. Though it is found in smaller populations and less frequently in Texas, they can be problematic in more Mediterranean – like climates, such as California. They can out-compete native snails for habitat.
They are edible, and at various times have been a very popular dish in Europe, from Spain to Morocco. One idea as to how to control the population in California is to put them on the menu in local restaurants.
The preferred habitat of milk snails is rocky, bushy shrubland or grassland, but this one has been chilling on our patio door.
The link to my iNaturalist observation can be found here.
Reference: http://www.tsusinvasives.org/home/database/otala-lactea