One of the interesting things about Marvel Comics is how seamlessly they integrated horror characters into their mainstream universe. A lot of that, of course, is just convenience. Marvel is, after all, a superhero publisher, so even when they do a comic about Dracula or, say, an actual demon from Hell who runs around with his head on fire punishing sinners with his supernatural abilities, they still just treat them like superheroes that are just part of this bigger, weirder world.
As a result, while they might all get lumped in together, they never really stay cooped up in some spooky corner, and if you're the type to dive into the quarter bin to look for a few cheap scares, that makes it pretty easy to find a spoooooky Halloween back issue. Sometimes Dracula shows up in X-Men and hits on Storm for two issues. Sometimes Blade joins a team of British heroes and helps fight aliens. And sometimes... sometimes Spider-Man gets kidnapped and strapped to a table with Frankenstein so that some weirdo you've never heard of can make "MONSTER SUPREME."