BACKSTORY
It is an unnamed ghost entity that's been lingering in the lot for an unspecified amount of time, memories long gone from the years.
A man moves in--scruffy, tired, kind. He can see the entity. He's pretty chill and hangs out with it, makes sure to come home every night to keep it company.
This man is revealed to be a social outcast and is quite suicidal so he moved somewhere where he can die alone. He muses, "in my old age, somehow, I still don't know how you can just... Love yourself. It's hard. So hard."
Eventually, he dies. He doesn't become a spirit, he just... Disappears. Out of grief, the ghost tries to possess him, reanimate him, but it's no use. He's gone.
Percival's current ghost form is based on that man.
"look, percival. I'm you. You're me. And I love you. So in the end, you love yourself through me." (irony that he obviously does not have self-love and self-respect, instead latches on to outside factors for worth)