The Dung Cannon-ok this one seems more like a Neopet weapon with more violence:
Dung’s Dual Poop Cannons - Savage Dragon
One of the many throwaway villains that graced the pages of Savage Dragon, Dung is about as static as a character can be. He is a walking poop joke, armed (literally) with two sewage cannons. Where all that crap comes from remains a mystery, but the fact remains that Dung has one of the greatest weapons in comic history.
The Bowel Disruptor – Transmetropolitan
Spider Jerusalem’s weapon of choice, even beating out a good old-fashioned boot to the groin. The Bowel Disruptor does pretty much exactly what it sounds like it would with settings that include:
Shat Into Unconsciousness
Unspeakable Gut Horror
And last but certainly not least, Burning Anal Geyser.
Tempting isn't it?
Too bad I don't have it in me to be a comic book evil villain. darn it. I think I got zapped by one though.