That's my guess based on that image.
These things get out of control! Serious pests!
Good for turning over substrate though, but they mainly eat and breed in the top layers, once established they easily proliferate as they (eggs, young) are protected by the substrate, soon you will be overrun, it is my number one not to have snail!
They look nice though and can serve some good functions but they always get out of hand.
Once the substrate looks like it's boiling (over populated with snails) pretty much the only way to deal with it is a complete tear down. Even snail eaters have trouble keeping on top of these.
(Based on my experience with them, other views may vary)
Regular snails are easier to control as there are several tricks that work on them but these guys don't seem to fall for the same catch methods.
If it came in on plants, it is most likely is a pest.