These latter two points may help explain why the film became something of a cult classic in the 1970s; although it doesn’t quite explain why a writer and composer pair named Howard Ashman and Alan Menken decided to take the bizarre step of adapting it into a stage musical. Ashman and Menken would go on to have many successful collaborations together – winning Oscars for their work on The Little Mermaid and Beauty And The Beast before Ashman’s death in 1991 – but the Little Shop of Horrors musical was their first big hit.

The stage show opened in 1982 as an Off-Off-Broadway production, before transferring to Off-Broadway (a full Broadway show was considered, but Ashman and Menken felt it was better-suited to the smaller theatres). Where the original film saw the hapless Seymour accidentally stumble his way into murder, the musical more explicitly takes on the shape of the Faust myth – with the plant (renamed Audrey II from the original’s Audrey Jr.) promising the nerdy schlub fame, fortune, and the love of his human namesake if he goes along with feeding him.

The musical plays fair by narrative rules, in giving Seymour his comeuppance at the end. In the stage show, as in the original film, while he’s ostensibly the “hero” Seymour is a largely pathetic and not especially likeable figure. The audience is therefore invited, just like in Faust, to approve of his downfall – even though, in this case, his actions have the unfortunate side-effect of unleashing a wave of man-eating plants across the world.

While much of the humor in the original film had arisen almost unintentionally as a result of the slapdash production, Ashman and Menken’s musical successfully blends the dark and bleak nature of the story – and its ending – with jaunty, upbeat rock and Motown-styled musical numbers and surreal gags. The songs showcase the pair’s effortless knack for a memorable tune, and it was no surprise that the play was an immediate hit, winning several awards and becoming one of the longest-running and highest-grossing shows in Off-Broadway history.

Equally inevitable, then, was the musical’s adaptation back to the screen – but the nature and scale of the production were still something of a surprise. David Geffen, one of the producers of the original show, initially sounded out Martin Scorsese about directing, but plans to shoot the film in 3D ultimately fell through, and in the end Frank Oz was approached. A budget of $25 million put it towards the top level of films Warner Bros were releasing at that time, and was an enormous show of faith in the source material and its ability to become a mainstream hit.