From time to time after the rain, here, in Sweden, it's possible to see interesting slugs on the roads. The rainy weather this summer made the population of them really boost. Until a couple of days, I realized that this creature isn't much of a vegetarian. I mean they do eat the vegetables in the gardens but would easily eat their brothers, the black slugs. The local newspapers printed the reports >> and one of them a list of the ways how to fight them. The killer slugs (Arion lusitanicus) resist even the boiling water. However if you put a jar with the beer, they tend to go in and drown there :P. Pretty wasteful way though.
There is one type of ducks that eats them. But when there are too many of slugs, ducks become fat and lazy.