One episode number one fan

This mainly applies to television series that have ran for over a year. One episode number one fans are people who see one episode of a popular television show and try to integrate themselves into the fandoms of said show much to the annoyance of actual fans of the show who have been there since day one. They will usually try and strike up a conversation with an actual fan but most fans are not interested in somebody who knows barely anything about the series and will ignore them. This usually leads to them becoming aggressive over not being included in a fandom they know nothing about and will often accuse the fans of gatekeeping.