The Haunting Of Hill House: 7 Most Chilling Fan Theories

There have been many theories surrounding the black mould found at Hill House. One of them is that Steven was right all along – there aren’t any real ghosts at all, and it’s mental illness that runs in his family. Black mould can apparently cause psychiatric symptoms, which can explain what happened to the Crain family.

Olivia seemed to be the main meal for the house due to her “sensitive” abilities, but the mould could have caused her mental health to decline to rapidly. So this either happened alongside the supernatural happenings, or the supernatural happenings were a psychiatric symptom that bled into adulthood. Other explanations within this theory state that the mould could have caused mass hysteria which is why they all saw the same things.

But the most haunting fan theory relating to black mould is that it’s actually a source of evil. It could be an evil entity that is controlling the house and is digesting everything within it, rather than the House gained its darkness elsewhere (such as Poppy and William Hill).