Please don't list this on a work's page as a trope. Examples can go on the work's YMMV tab.
Nightmare Fuel: Avenging Disco Father
The otherwise hilarious Blaxploitation film has an incredibly disturbing scene in which a woman high on drugs cooks her baby and serves it to her family. The whole movie has a pretty strong Drugs Are Bad message, but for the most part it's sort of tongue-in-cheek. Until then.