Since I don't know how serious this villain is supposed to be, or the camp factor of the story, I will offer Potty Mouth!
Sid Ferguson, veteran sanitation worker in (insert superhero city name here), was thought dead last year when he fell into a half-empty waste storage tank at the local Super Fund site. Sloppy safety standards and equipment and an unwillingness on the part of his supervisors to take responsibility led to a coverup of the accident, and Sid simply 'going missing,' and being quietly taken off the city employment rolls. His lack of a family or any close connections made the coverup even easier, or so the crooked administrators thought.
Behold! The world will now suffer for its transgressions, punished by Potty Mouth! Standing a squat 5'8", with a soft gut, wearing a filthy once-white tank top undershirt and utility pants, this bald, hairy-shouldered creep has to major superpowers: first, he exudes a cloud of nauseating stench at will, blurring the vision and burning the lungs of those within range. The stench is also enough to incapacitate. Second, he is able to blast walls, cars, doors, and his foes with a high-pressure stream of raw sewage, projectile vomited at will (although, like a dragon's breath, he has to recharge now and again). He is also more resilient to physical damage than the average person. And although it is not a superpower, he is also known for his exceptionally vulgar language.
Potty Mouth keeps his lair somewhere in the abandoned warehouses at the edge of town, lurking around toxic waste and the rusted skeletons of the city's industrial past. He engages in the typical brand of bank robberies, jewelry heists, and other property crimes. Due to his preference for living in filthy conditions, he has no known longterm associates, but has at times been hired on by other gangs and criminals for his ability to control the battlefield (stench) and strike from range (projo puke).
I imagine him to look like Paulie, from the early Rocky movies, but much dirtier, of course.
As for the mechanics of this menace, I see him as having some level of Damage Resistance, enough to let him shrug off punches and being smacked with a bat or something like that. I'd also give him some small amount of automatic healing, enabling him to get up after being knocked down several times. Nothing too much, but enough to give lower-level heroes a challenge. For his stench, I'd treat it like a spell that required Concentration, and the longer he maintains it the worse it gets for people, and the longer it can reach - basically, he would impact everyone within 10 feet, and then each round it'd expand outward 10 feet (in all directions), up to a maximum of maybe 50 or 60 feet. I'd have the first effect be blurred vision, then stun on top of that, followed by puking uncontrollably, followed by unconsciousness. The longer you stay in it, the worse things get for you.
As for his sewage blast, it'd have a range of up to 100 feet, but would do less damage past about 50 or so of that. It'd knock people over, do so blunt force damage, but would also stun and sicken those hit full on with it, and would also stick in place those knocked over by it.
