As I mentioned in my last post, Henry Selick has indicated that Jack Skellington makes an appearance in Coraline. Indeed, this page lists Coraline trivia and says that Skellington appears as the yolk when Coraline's other mother cracks open an egg. In fact, I linked to the footage - - when I mentioned Adam Sager's work, digitally enhancing the Coraline footage:
Adam C Sager's Coraline VFX REEL from Adam C Sager on Vimeo.
Here's the best I could do providing a still:
*Buy Coraline Dunks at eBay.