Aliasing horror → nightmare_fuel
Link to alias

Reason:

Although there's some overlap with monster and scared, the general usage seems identical to nightmare_fuel. Which has always been bit of a vague tag..

There might be some subtle difference between these, but it seems to hard to define. Best to combine them, I think.

I'm against this alias.

nightmare_fuel wiki states:

The tag scary, creepy or similar does not refer to this

If the post has you saying "Ah, spooky ghost" it is not nightmare fuel.

If the post has you saying "Oh god what the fuck!" or "Why would you draw that?" then it should be tagged nightmare fuel.

People seems to be using horror tag for both of the meaning. I'd rather alias it to invalid_tag and manually replace with nightmare_fuel or scary.

Invalidate

It's a mix of emotions, nightmare fuel, and stuff that doesn't really fit in nightmare_fuel, so instead I cleaned it out and approved alias -> invalid_tag