If they showed this move in high school Sex Ed, teen pregnancy and STIs would drop to zero.
An unethical scientist (Fred Doederlein) uses his teenage lover (Cathy Graham) as a guinea pig to breed a parasite that turns people into sex maniacs. He murders her but the damage is done and the parasite spreads through all the residents of an isolated luxury apartment building, despite the best efforts of the resident doctor (Paul Hampton).
Okay, so this movie is gross on so many levels.
Level 1: Intentionally. Cronenberg has made an entire oeuvre of body horror and this is no exception. Lumps swell under skin, slithering around inside the bodies before a hand-sized leech is expelled in bloody vomit. It's nasty but acceptable.
Level 2: Disease horror. This is not the movie to watch in the middle of an actual pandemic. I just wanted to scream at all of these people for not washing their goddamn hands or wearing even the barest bit of PPE. These are supposed to be doctors and a nurse for God's sake. Again, though. Horror movie.
Level 3: Sexually. Everybody gets raped. Everybody. It's A. Lot. There's a ton of gratuitous nudity. It's the 70s. Okay. But not a single woman in the film owns a bra? Also, yikes.
Level 4: Violence against women in particular and some smattering of racism. Did I mention all the raping? Plus, the main character pointedly ignores the only Black female being assaulted in front of him to waste three bullets on a guy who had already committed murder.
Level 5: Implied pedophilia. The gross dude who engineered the parasite is casually mentioned to have started a "relationship" with the girl he murders when she is twelve. This goes unremarked upon for the rest of the film. There is a scene in an elevator where a parasite-ridden waiter attacks a woman standing with her prepubescent daughter. It cuts away but the implication is strong, bolstered by a later scene where the elevator opens and the waiter and child are sharing some gross, strawberry jam-filled pastry over the disheveled body of her mother. Critical high level of nope there.
In terms of sheer audacity of violence and gore, it rivals The Last House on the Left, Hellraiser, and any place exploitation crosses with horror. It's not a fun watch. I found it kind of a slog, if I'm honest, but I can see its influence in other, later films which is worthwhile. It's currently streaming on the Criterion Channel or for free on Tubi.