10 Risky Film Moments Directors Thought They'd Lose You

Back to the Future is undoubtedly one of the most beloved movies of all time, yet this was result of a tremendous amount of re-working during pre-production, principal photography, and post-production - most of all that the time machine was originally a fridge, and initial lead Eric Stoltz was re-cast with Michael J. Fox.

But once the film had actually been shot, director Robert Zemeckis found himself concerned that one scene might turn audiences off, when Doc (Christopher Lloyd) and Marty (Fox) send Doc's pet sheepdog Einstein a minute into the future in their first successful time travel experiment.

In one of the film's early test screenings, audiences weren't told that it was a comedy, and so according to Zemeckis and co-writer Bob Gale, the atmosphere in the screen became incredibly tense as Einstein was being sent through time, with audiences seemingly believing the dog could very well perish.

Within that context it's a totally understandable concern, given that the scene does rather milk the suspense of Einstein's smoky return for every drop it's worth.

Yet the scene ultimately ended up playing well on general release, likely thanks to a marketing campaign which aggressively played the comedy card and ensured audiences knew they were sitting down for a light sci-fi adventure - you know, rather than a David Cronenberg film.