Evidently it's a common known fact that beer attracts slugs. If you put some out at night, they will crawl into the liquid, party till the sun comes out and then drown. I'd never heard this until this year, but it definitely works.
My mother-in-law has been fighting to save her hostas from the hungry little guys and she gave about 50 a great going out party over Memorial weekend. Rest in peace little slimy fellows.