Pila ampullacea is a freshwater snail originally from the Southeast Asia. It belongs to the family Ampullariidae.
These snails are edible and they are regularly collected and consumed in Vietnam in various ways. They should be parboiled, because raw or undercooked snails can transfer parasites such as metacercariae of Echinostoma causing echinostomiasis.
I thank my friend Jan Vrba who kindly provided the photo.
This food was served in a restaurant under the Vietnamese name “Ốc hầm thuốc bắc”, that means approximately something like “Slowly cooked snails, (recipe from) northern (traditional) medicine”. It is just a name for attracting customers. I think, they should write word cuisine instead of medicine. However snails are important source of proteins, especially in areas where proteins are scarce.