The significance of the monster spray in the story is that it gives the characters, usually children, a sense of control over their fear. Instead of being helpless against the idea of monsters, they have a tool, the spray, to combat it.
It's hard to say for sure. 'Tar' could be a completely fictional creation or it might draw inspiration from real-life situations and then be embellished.
Well, it could be. But often, even if inspired by real life, movies or books might tweak things for dramatic effect or to make the story more engaging. We'd need more info on 'Tar' to know for certain.
Tar fiction is not a commonly known term. Maybe it refers to some fictional works related to tar or something made up using the word 'tar' in a creative context. I'm not really sure though.
I don't think so. Tar is not typically associated with a ghost story. It's more likely to refer to a substance or something else unrelated to the supernatural.