9. The Nightmare Before Christmas (Batman Forever)
Prior to the 1995 release of Batman Forever, Tim Burton's The Nightmare Before Christmas contained a number of Easter eggs relating to Batman - the director having helmed a couple of the Dark Knight's movies prior to his Halloween-themed animated feature. In a nod to the director who preceded him in charge of Batman movies, Joel Schumacher then gave a nod back to Burton in Batman Forever. For starters, he dressed one of the trick or treating characters who approach Wayne Manor in Jacks Pumpkin King outfit from the film (as seen in the picture above) and then he modelled the Dr. Burton character on Burton himself (with a hint of The Nightmare Before Christmas thrown in for good measure). The character's outfit included a bow-tie that was clearly modelled on the one worn by Jack Skellington in the excellent animation.