Sludge is a comic book series from Malibu Comics, set in the Ultraverse. It was created by Steve Gerber, Gary Martin and Aaron Lopresti. It depicted a dirty cop called Frank Hoag who was killed by the local mafia and was transformed after his death into a superpowered and viscous creature, called Sludge.

Stephen Ross Gerber was an American comic book writer and creator of the satiric Marvel Comics character Howard the Duck. Other works include Man-Thing, Omega the Unknown, Marvel Spotlight: "Son of Satan", The Defenders, Marvel Presents: "Guardians of the Galaxy", Daredevil and Foolkiller. Gerber often included lengthy text pages in the midst of comic book stories, such as in his graphic novel, Stewart the Rat. Gerber was posthumously inducted into the Will Eisner Comic Book Hall of Fame in 2010.