A human being who, often due to an excessively chilli-heavy diet, has not produced a solid stool in years.
Simon, a notable Sludge Cannon, is barred from every public lavatory in the north of England.

"Mummy, does Uncle Simon wear plastic underwear because he's a sludge cannon?"
"No, dear, it's because he's a massive pervert."
by Lancaster's Second Finest June 12, 2016
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