I love the fact that it's so horrible that they eat excrement and small rodents. Errr... that's what slugs do when they aren't munching our veg, they clean up the crap that gets left lying around!
As for the cannibal bit... we have Leopard Slugs (first recorded in Britain in 1678... so most people probably still think they are bloody foreigners!) in our garden, they are most impressive when hunting down other slugs, being anything but sluggish, and they also have the most incredible sex life.
http://vimeo.com/16731697 You won't find me trying that!
Adrian