In the 1983 Hong Kong horror sleazefest Seeding of A Ghost (a.k.a. Zhong gui), a cab driver hits a warlock with his taxi. Naturally, this freak accident leads to ghost sex and a tentacle monster right out of The Thing.
Later in this schlocky flick, the cabbie's wife is later killed by a gang of thugs, and the cab driver hires the warlock to get revenge on those responsible for her death. To perform the ritual, the sorcerer must be first summon the man's dead wife's ghost and watch it have sex with a corpse. You may be weirded out by that sequence above, but nothing will prepare you for the film's final scene...
See, the cab driver's wife was having an extramarital affair with a suave gambler, who in turn has a pregnant wife. When the cabbie casts the magical ghost sex spell, the gambler's wife gives birth to a tentacle baby who starts attacking a bunch of confused couples. This is why you never ever hit a warlock with a taxi.