Eliza (Knock Knock)
Eliza was the mother of the Landlord.
In 1947, she caught a deadly illness and the doctors had given up on her. However, her son brought her what he thought were insects from the garden to try to cheer her up. They were in fact space termites. Once she was left alone and left her music box open, the sound awakened them and they sensed that she was sick. They thus began transmuting her body into wood in order to preserve her before she died. When her son discovered the space termites' abilities, he tamed them and for the next seventy years, would lure young people looking for accomodations to their house. The termites would then proceed to absorb the victims and transfer their life energies into Eliza to prolong her life.
In 2017, Bill Potts and a few other classmates looking for student accommodation were invited by the Landlord into their house. Once the Twelfth Doctor, who was helping Bill move in, deduced something was amiss, the house proceeded to absorb Pavel, Paul and all the other students except for Bill and the Doctor.