Some TMNT stuff really isn't for little kids.
The human exterminator who would become Scumbug first appeared in Teenage Mutant Ninja Turtles Adventures issue 10. He was hired by Oroku Saki under the guise of a businessman to deal with the roach problem in the basement of Shredder's current hideout, disguised as "Saki Inc" to fool the exterminator.
Chasing a cockroach, the exterminator slips on the messy floor and falls down a manhole filled with carelessly dumped Mutagen. The exterminator was mutated into a hideous cockroach mutant. Driven insane by the experience, the exterminator fought the Turtles in the sewers, mistaking them for green giant coachroaches and was later confronted by Wyrm (a mutant flatworm). As Scumbug and Wyrm fought knee-deep in sewer water, they accidentally got electrocuted by nearby power lines.
However they would both return in a future issue, and were slated to return in the final story arc of the series, Forever War, before its cancellation.
As an exterminator, he seemed to be a normal if clumsy businessman without any evil inclinations.
After turning into Scumbug, the exterminator went insane and still thought he was a normal human. He believes everyone else he encounters is a giant bug.
Mutanimals TV series
Scumbug was planned as a villain in the unproduced Mutanimals TV series.