It's actually quite pretty (again, relatively speaking), but this slug is most likely an Arion rufus, a species that's native to Europe, but has been found in British Columbia and is apparently now also at large in Ontario. Hermaphroditic in nature, some slugs can even knock themselves up, so it only takes a single invader to build an army. Once the population is established, the slugs become (and I quote) the "slow moving lions of the vegetable world."
So how do you get rid of them? The story offers two possibilities. First, you can leave out beer for the slugs. They're attracted to fermented yeast, but they're a little dumb and they can't swim, so they'll end up crawling in and drowning themselves. The other option: Collect the slugs when they come out at night and "immerse them in boiling water." The article, unfortunately, does not mention whether you can then eat Arion rufus in a nice butter sauce.
10 cm Etobicoke Slug a Big, Slimy Mystery in the Toronto Star
(Thanks, Margaret Atwood. Yes, that Margaret Atwood.)
Image taken by Etobicoke, Canada resident Lisa Bendall. Used under fair use.
