Oh boy, where to begin? There's a bunch that range from implausible, to unsettling, to simply absurd:
- Crookshanks used to live with the Potters
- Hagrid is a Death Eater
- Voldemort's rudimentary body was Bertha Jorkins' unborn child
- Draco actually loved Hermione
- McGonagall had an affair with Crookshanks
- Harry hallucinated the events of all seven books
- Wizards used to sh*t on the floor and vanish the evidence
- Snape was Harry's real father the whole time
- Mrs Norris is a maledictus and Filch's wife
- Voldemort secretly had a daughter