Matt Haag is nicknamed The Professor. He was invited to the party by Joey Graceffa.
Episode 1 - An Invitation
Episode 2 - The Ungodly Machine
Episode 3 - Buried Alive
Episode 4 - Mannequins
Episode 5 - Freak Show
Episode 6 - Did Someone Call For An Exorcist?
Due to a failed exorcism, Matt murders Sierra, thus, decides not to care about anybody's lives. Because of this, they all turn against him.
Episode 7 - Mermaid Tails
Matt dies this episode by failing to complete his doll house correctly, causing him to drink poison twice. He was against Tim.