The set-up: Back in 2000, the idea of a successful superhero movie was dead in the water. But in a deleted scene from the original X-Men, exists the most mind-blowing franchise crossover of all time. Well, in a way.
The Super-LOLs: During a dramatic scene, Jean Grey, Cyclops and Storm run into shot. Only to be interrupted by a cast member in a naff Spider-Man suit running up behind them to save the day.