This is Spookums the ghost, although that name was never actually given to him/her/it in the book. It was originally planned to have Spookums be a regular cast member and join the DeMonte family, but for some reason as I was plotting out this chapter it just felt a lot funnier to make the little punk an antagonist who drove the family crazy for no real reason…other than being a punk is funny.
Spookums’ design owes less to classic film/literary ghosts and more to ghost Pokemon (yes, I played the Game Boy games twenty-something years ago, and yes, my team always included a Gastly/Haunter/Gengar).