Link: https://archive.org/download/chud-1984_202408/CHUD%201984.mp4

C.H.U.D. is a low-budget horror movie that not many people watched but nearly everyone who walked into a video rental store saw the box and commented on the title. Then an episode of The Simpsons made reference to it (Homer was attacked by the pimps and the CHUDs during a visit to New York City) and since then the word "chud" has entered into modern vernacular.

When a NYC cop named Bosch ("Captain Bosch", no first name given--Christopher Curry) goes searching for his missing wife, his investigation puts him in contact with A.J. "The Reverend" Shepherd (Daniel Stern of Home Alone fame), who works with the homeless population and especially "Undergrounders", a segment of people who live in the sewers and subway tunnels. They are later joined by photographer George Cooper (John Heard), whose girlfriend, Lauren Daniels (Kim Greist) has also been attacked by something living underground. Slowly they gather evidence of a government cover-up, which involves mutant creatures living in the sewers, called C.H.U.D.s (Cannibalistic Humanoid Underground Dwellers). Naturally they fight the monsters and a bunch of people get killed, you know how these things go.

John Goodman makes a brief appearance as a cop. Also there was an in-name-only sequel, CHUD II: Bud the Chud (1989), wherein the title character is more of a zombie.

Looks like the whole movie is on Youtube too: https://www.youtube.com/watch?v=mmxbD1lTLEk

Movie Trailer

I never knew that chud was originally an acronym. That's wild