It supposedly took Steve Martin six weeks to film all his scenes for "Little Shop of Horrors" (1986).

It supposedly took Steve Martin six weeks to film all his scenes for
"Little Shop of Horrors" (1986). He contributed ideas such
as socking the nurse in the face (originally he was to knock her out
using his gas mask) and ripping off the doll's head.
While filming the scene in which Dr. Scrivello pushes open the double
swinging doors to Audrey's apartment complex, Martin cut his hands
when the glass windows shattered. As a result, in the final cut, he is
kicking the door open. The outtake of Martin cutting his hand can be
seen as a special feature on the DVD and Blu-ray releases.
After Tim Curry declined the role Frank Oz considered both John
Travolta and Dan Aykroyd for the role of Scrivello in case his next
choice, Martin, proved unavailable. However Martin ultimately was able
to accept the role. Robin Williams was also briefly considered, but
told Oz he didn't want to do another musical after the failure of
"Popeye" (1980), and because he and Moranis had starred in
Club Paradise (1986) released a few months before this movie which had
flopped with both critics and audiences.
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