Late one evening, I went to the garden to fetch our resident assassin's food bowl. It being after sunset, I saw no more than the silvery outline of the steel bowl as I reached to pick it up - so the soft squishy/slimeyness that met my fingers beneath the rim came as quite a surprise. An inspection in better light revealed a solid mass of slugs on the walls of the bowl, drawn by the rich odor of the protein the bowl had contained. The numbers were really incredible - an infestation of almost biblical proportions.
Revenge for this outrage was swift. Having terminated several dozen of the intruders with extreme prejudice, I deployed my secret weapon near the food bowl's usual spot. A jam jar one third filled with beer, dug in so that the lip is at ground level makes a simple and convenient death trap: it might even be humane. Just a day or two later, the trap had claimed the lives of dozens of drunken slugs.