The Little Shop Of Horrors (1960)

Starring Jonathan Haze, Jackie Joseph, Mel Welles, Dick Miller, Myrtle Vail
Directed by Roger Corman
(actor & director credits courtesy IMDB.com)

A bumbling flower shop employee breeds a plant with an unhealthy appetite for human blood, and is soon urged by the plant to get it human bodies to consume.

The majority of people probably know the off-Broadway musical or its 1986 film adaptation, but probably don't know the story originated in this quickie horror comedy from producer/director Roger Corman and screenwriter Charles B. Griffith.  Despite the low budget and the more primitive special effects, this version holds up remarkably well, with a more macabre tone, and Haze in fine form as a less geeky but still sad sack Seymour with a goofy logic that he makes almost seem like common sense.  In filling the film with offbeat characters alongside Seymour, from the flower-eating Mr. Fouch, to the hypochondriac Mrs. Krelboin who mixes medicines into the meals she cooks, to the pain-loving dental patient (played by future legend Jack Nicholson), Griffith provides unconventional humor in unexpected places, much of which didn't end up making it into the musical.  That makes this a unique black comedy that doesn't deserve the obscurity heaped on it by its more famous adaptations.