For a genre with many depictions of literal hell, it should come as no surprise that so many horror films end up stuck in development hell. However, unlike the ghouls and demons that break free from the underworld, some pictures never escape from their fiery prisons.
It only takes one minor thing to go wrong to completely derail a film's production, leaving the world bereft of what could have become a new classic.
Whilst this isn't just limited to horror - far from it - some of the most exciting ideas in the spooky subsection have been left victims of studio interference, backstage meddling, or just plain old bad luck.
These ten movies were at the very least seriously discussed. Some had scripts written, some even began production, whilst others were fully completed before being shut away for good.
Maybe one day we'll see one or more of these films get an actual release but, for now, they exist only in our heads as tantalising prospects we may never get to watch.
Although maybe that isn't so bad. After all, you can't be disappointed by something if it doesn't exist.
10. Halloween Vs Hellraiser
Horror history is jam-packed with crossovers pitting famous movie monsters against each other.
Frankenstein and the Wolf-Man, Freddy vs Jason, all those awful giant animal vs other giant animal films. Look, we never said these crossovers always were good. But for every combination of classic creatures we did get, there are about a dozen that never saw the light of day.
One example is an idea floated around in the early 2000s that would have seen the Halloween franchise's big bad go up against the main antagonist from the Hellraiser series.
According to Doug Bradley, the actor behind Pinhead since the original Hellraiser film, his most famous character almost squared off against Michael Myers. That was, until Dimension Films rejected a script for the picture not once, but twice.
The studio's reasoning was that they believed the upcoming Freddy vs Jason movie would flop. As it turns out, they were about as wrong as it is humanly possible to be wrong.
Plans were quickly changed and John Carpenter himself was in talks to direct the feature, but the idea got shelved when Halloween producer Moustapha Akkad said no.
Shame, this would have been really fun.