Friendship on the House on the Hill
One of my favorite board games is Betrayal on House on the Hill. It’s a semi-cooperative board game. The game has two phases. In the first phase, the players work together in exploring an old house. After a random event occurs, the game shifts into its second phase: One players’ character is randomly chosen to be a traitor. The traitor works to kill off the other players’ characters, while the other players work together to escape that fate.