The Island of Doctor Moreau | Image: New Line Cinema
Sometimes "movie magic" can only be considered so because the onscreen action belies horrible conditions behind the scenes. Whether the director and actors are at each others' throats, one or more members of the cast are making diva/divo demands, environmental conditions are unbearable or other difficult circumstances are present, things on the set can turn miserable on a dime.
Take, for example, the 1996 film The Island of Dr. Moreau. Add together the following: warlocks, puma pee, treehouse demands, jungle escapes, and that's just the tip of the proverbial iceberg. Get the full story, and that of five other films that were hell behind the scenes, at Cracked.