Snails...we have them here at the new house that are the size of a half dollar. I picked one out of a pot the other day and sent it flying. I find a penny in the pot will help..some line their shelves with copper strips. I know pennies work because the next day you find a puddle of goo with eyes. lol Beer on a plate works really good too. I just never have any around so I use the penny thing.