Mary Terrafino, or Mother Mary, jumped off a cliff, having lost her sanity by overworking in the Day Care and hearing Orsay and Nerezza talk about how leaving the FAYZ (either by death or "poof") will transport you to the other side. However, Nerezza is the Gaiaphage's avatar and is manipulating Orsay into believing she can see the dreams of the adults after she visited the mineshaft with Bug and Edilio hoping to see the Gaiaphage's dreams. Mary wasn't originally going to jump and promised her brother, John Terrafino, that she would never leave. However, she later found out that he lied to her about stuff going on in the council, (he was the youngest member) onAstrid's accord, and she contemplated leaving a bit more. It also should be noted that she had depression and several eating disorders that could have contributed to the jump. It was mentioned several times that there would be a red setting sun and Mary saw her mother making peanut butter and jelly sandwiches for all of the littles saying they could enjoy them with their families in a hallucination caused by the Gaiaphage. Orsay leads Mary to believe her prophesies by saying that her mom got John a skateboard and talked about how jealous Mary was. She told her this because Mary called her a false prophet and told her to stop lying to Francis, a volunteer at the daycare that "poofed" because of Orsay. Before he left, he gave Mary his watch. It's likely that since Nerezza was a spawn of the Gaiaphage, she obtained the Gaiaphage's ability to dig into other's minds and see their memories. Using this power, she may have looked into Mary's mind and found the memory of the skateboard and then replayed that memory into Orsay's mind pretending to be Mary's mother.
Now believing Orsay and Nerezza, she attempted to bring the littles out of the FAYZ by having them all hold hands as she jumped off the cliff at Clifftop on her birthday and take the "poof." The children would've died, if Brianna and Dekka hadn't arrived. Brianna was able to use her super speed to catch Justin, the most main little, when he was dragged off the cliff. He tried to leave earlier but Mary's grip was too strong. Dekka suspended gravity and saved the others. Howard dubbed it as "Mary's Big Jump," he is responsible for naming many things in the FAYZ including the FAYZ itself. Sam later says that he thinks it's sad how people will remember her as the crazy anorexic that tried to kill all the littles.
Mid-jump, Mary 'poofed' out of the FAYZ, and in Fear, you find that her and Francis end up terribly disfigured when they end up outside the FAYZ. She is described to have lobster-red skin and a slurred speech from the result of teeth growing out of her cheeks and having surgery. One eye is said to droop downwards like a blurred smear on her face that she probably couldn't see out of. She was found by bikers that called animal control, making an "honest mistake" that she was a mangled animal. Francis was also disfigured, but he couldn't speak, as it was said that he had no facial features such as a mouth and was feed through an IV. His fingers were all joined together, making his hands useless. His arrival was televised and they both died four months after Mary's Big Jump from a disconnection with the "J-waves" but not before Mary cries about having killed the littles and informing the doctor's that Little Pete caused the FAYZ, but they were very skeptical that a five-year-old could have the power to create the FAYZ. Back in the FAYZ, Orsay confronts Nerezza about her doubts and explains that she thinks that they shouldn't have driven Mary to jump. Furious, Nerezza strangles Orsay on the beach and leaves her lifeless body there like roadkill.