Throw Momma from the Train (1987)

Larry Donner is an author and writing professor who tutors people that want to write books. Larry's life has become a misery when his ex-wife Margaret has published a book he wrote under her name and has gotten rich over it. Owen Lift, one of Larry's students, offers Larry to kill Margaret, and in return Owen, wants Larry to kill his horrible mother. Larry thinks it's a joke, until he learns Owen killed his ex-wife. And Larry has now become the prime suspect.—Daniel Williamson

From IMDB:

One of the best dark comedies

Larry Donner (Billy Crystal) is an author suffering from writer's block. He hates his ex-wife Margaret (Kate Mulgrew) who stole his book, and published the best seller as her own. Owen Lift (Danny DeVito) is one of Larry's clueless writing students. He hates his hateful mother (Anne Ramsey). Owen keeps stalking Larry about his writing about murder. When Larry suggests Owen watch Alfred Hitchcock's 'Strangers on a Train', Owen assumes that Larry is saying that he will kill Owen's mother if Owen kills Larry's ex-wife. Then Owen goes to Hawaii to kill Margaret. The problem is that Larry has no alibi, the cops are on his case, and Owen expects Larry to kill his mother.

This is a great dark comedy. Danny DeVito is terrific as the idiot. Billy Crystal is neurotic and angry. They have great chemistry together. Anne Ramsey is the best ugly bully. It's Danny DeVito's big screen directorial debut. He does a good job letting the actors room to work. It is well worth a watch.

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