The machine itself looks like a giant metal gyroscope, consisting of a round metal core surrounded by rotating spiked rings, almost fully immersed in a deep pool of blood, completed by a walkway leading to it. It was "invented" by Walter Sullivan when he was a young boy, the purpose of which is to kill anyone who gets near. In the final battle, Eileen Galvin is completely possessed, walking slowly towards the core. Her speed varies on how well Henry Townshend defended her throughout the game.
The core of the machine represents Walter himself, and his wish to return to his "mother's" womb. The spiked rings symbolize his wish for protection, believing that surrounding himself with spikes will keep him from harm.
- The contraption appears on the soundtrack cover.
- If Eileen walks into the machine before Henry is able to save her, the player will be able to hear a horrific shriek. 
- Even if Eileen is killed by the machine, the news proclaims that she passed away due to her injuries. This is because in the Real World, Eileen's physical body is still in St. Jerome's Hospital.
- There is a child's drawing near Room 105 representing a woman in the machine being chopped in pieces. It is most likely that this was drawn by Walter's younger self.
- The machine greatly resembles the gravity drive of the titular ship the Event Horizon in the 1997 science fiction horror of the same name.
- If a Holy Candle is placed near Eileen while she is walking towards the machine, its effect can slow her down, should the player feel her too possessed for safety.