Helloween is a cancelled movie that Dimension films planned on releasing in 2005.
In 2003, New Line Cinema made Freddy vs. Jason, where Freddy Krueger from A Nightmare on Elm Street fights Jason Voorhees from Friday the 13th, Dimension films saw the success of it, and they decided to make a movie similar, they wanted to make a film where Michael Myers from Halloween fights Pinhead from Hellraiser. They planned it in 2005, it was going to be called Helloween, matching up the two titles.
Why it was canceled
At first it seemed legit, especially since John Carpenter, Clive Barker, and the actor who plays Pinhead, Doug Bradley, all thought the film sounded interesting to make, but Dimension films created a poll, seeing what the fans thought about this idea, but most of them voted that they did not want the film to happen, so Dimension films stopped development.