Lisa and I have an ongoing gross-candy contest, and perhaps the grossest thing we ever found was a plastic nose called Pick 'N' Chews, where you picked the gum or candy out of the nostrils.
Along these same lines, there is now the Hose Nose -- you strap it on your real nose and then let the liquid candy slowly driiiiip out to be caught on your tongue.
NEW GROSS-CANDY WINNER! Hands down! And this from someone who has actually eaten Gummi Maggots. (Via Candy Blog.)