Brutal Sorcery (Ling Pang, 1983)

Ling Pang's Brutal Sorcery is a nutty black magic Hong Kong possession-fest told in flashbacks within flashbacks about an extremely unlucky taxi driver who gets possessed by two spirits thanks to his own bad luck but falls headfirst into another possession a couple days after getting free of the first one thanks to his own stupidity. It's a fun and ridiculous film that drags a little in the final third before rallying in an epic showdown finale between two black magicians, one working for good (and much selfish glory), one working for evil.
Alan Chang is driving around Hong Kong one night in his cab looking for fares when he sees a woman walking alone. When he asks if she needs a ride, she turns around and shows him her scary ghost face. Terrified by seeing the ghost, Alan gets his fortune read. The cards aren't good. The fortune teller says the combination of the bad card reading, the ghost spotting, and Alan being born at 9:00 p.m. on the ninth day of the ninth month in the year of the dog means he'll probably die young. He's seriously freaked out but gets a good luck charm to hang in his cab, which completely placates him because he's kind of a doofus.
He hits the streets in his cab soon afterward and talks a middle-aged couple into accepting a ride even though they're acting spooky and keep warning him off. Despite his ominous fortune, goofy Alan is oblivious and takes them to a cemetery where they tell him to wait. The woman disappears, then the man has Alan take him to a different cemetery, where the man disappears. Alan is surprisingly relaxed about all this thanks to his good luck charm, but things get bad when Alan stops at an all-night noodle stand where the employee and the other customers act like possessed weirdos. When he gets home, Alan throws up the noodles and starts acting like a total weirdo. His wife, daughter, aunt, and uncle decide he's possessed and take him to a medium, who channels his possessors. It's the couple he picked up in his taxi, who were killed by a black magic spell mid-sexual encounter. The spell was placed on the couple by their families, who didn't approve of the Hong Kong-Thailand mixed relationship. They were buried in separate cemeteries, and their spirits only get to hang together once a year, when the black magic is strong. They have both possessed Alan and agree to un-possess him if he digs up their bodies and takes the remains to the woman's sister, who lives in Thailand. She will bury them together, and their spirits can hook up eternally. Complicated shit.

Alan seems to have no trouble grave robbing and delivers the goods to Thailand. While there, though, he forgets about his wife and kid and starts boning the sister. He finally tells her, three days into the affair, that he's married and is going back to Hong Kong. She says she accepts this news as long as he comes back three months later for a visit. The sister contacts the evil black magician who put the spell on her sibling and gets a spell in motion for Alan if he blows off their future rendezvous. Dumb Alan ghosts the sister, and the recently de-possessed cab driver is once again re-possessed, this time in a much deadlier "black magic death spell." He starts acting crazy and eating live animals raw, which concerns his family. He is also unable to perform sex. Every vagina feels impenetrable thanks to the hilarious curse. He finally owns up to the affair. His wife forgives him, takes him to another uncle who is a doctor, takes him back to the medium, and finally consults with a black magician, who reluctantly agrees to help fight for dumb Alan's soul. A black magic vs. black magic superfight ensues.
Holy fuck, that's a lot of plot. It doesn't really feel like it, as almost everything that occurs is goofy and hilariously dubbed into English and mostly quickly paced. It's hard to know if the dialogue is this weird in the original Cantonese or if something has been lost in translation. For example, the family is approached by journalists in the film's opening scenes, and the doctor/uncle tells them, "This is no time for that kind of talk," before responding to the next question with the entire story of everything that happened to Alan, possession-wise, much of which the doctor wasn't even around for.
The movie is visually pretty perfunctory, and the effects are just okay, but, except for a somewhat dull stretch at the two-thirds mark, Brutal Sorcery is lively and fun and extremely weird. Once available in the U.S. on VHS but now out-of-print, it can be seen as of the date of this post on YouTube. Check it out.