If you've never seen a Banana Slug, they are huge. The slugs I have been dealing with in my garden are the length of a dollar bill. 
The slugs have been all over my basil. They have also started in on the Italian parsley and the cilantro. I had to do something quick, before my dreams of fresh pesto disappeared completely. I had heard that slugs are terrific lushes and that, given a bowl of beer, they would quickly crawl into it and drown, happily slurping the brew. But, I have two dogs and didn't want to put a bowl of beer out for them to imbibe in, so I came up with the following solution.
I had an empty parmesean 
cheese container that was on it's way to the recycle bin, so I filled it about three quarters of the way with beer. I have seen slugs leave their slimy trails up the sides of buildings, but I didn't want them to work that hard at reaching the beer so I decided to bury it in the ground. The next day I checked it, but the slugs must have crawled up the side where the lid was and closed the top. 
I propped the top open with a small garden shovel which seemed to do the trick. Over the next few days there were five fat slugs in the container. The beer had turned them blue. I have since gotten some slug bait and sprinkled that in the garden. It is supposed to stop them from eating, and then they go back to whereever they live by day and die. It's a much better option than dealing with blue decomposing slugs. Yuck.
