This isn't an original idea but I can't get monster falls out of my head so I'm writing a fanfic.
Though now that I think about it, I have tried to make my Monster Fall's fic as unique as possible... Let's see how that goes.
Let's say that Dipper never went to gravity falls, but everything else still happens. Mabel defeated Bill with the rest of the town.
There both 17. Dipper been to multiple hospitals because of his anxiety, depression and suicidal thoughts. Dipper's father has been abusing him for years. Finally they stopped his father and he's in jail. Dipper doesn't trust anyone at all. He doesn't like being touch by other expect for Mabel .
Mabel trying to keep Dipper away from bad people. Mabel finds out that Bill is still alive. Dipper is still the kind and loving brother. gives up anything for her no matter what.
One day Dipper meets Bill in his human form.
the two have been meeting up in secret because of Bill. Dipper things he's a nice guy until Mabel shows up messing everything up. (bitch).
Bill slowly starts to fall in love with the young teen and Dipper starts to fall for the demon as well.
Note : Warning for suicidal thoughts, self harm and bad language.