12 Biggest Retcons In Harry Potter Movies

7. The Other Ghosts In The Great Hall Who Disappear

Perhaps thanks to the limits imposed on the budget for the films, most of the ghost-related story elements were left on the cutting room floor. We didn't get to see Peeves the Poltergeist at all or Nearly Headless Nick's Deathday Party (or the Headless Hunt) and the House Ghosts were mostly minimised aside from Nick and Helena Ravenclaw briefly.

But it clearly wasn't the intention back when the first film was made as the first time we see the interior of the Great Hall, all of the House Ghosts appear, but so too do other random, unnamed ghosts who float around in the Hall's roof.

They're barely mentioned, and then by the time the second film comes around they're all gone again.