The Gorge of Deception!
As the team wander deeper into the digital world, they found a ghost city that nests a horde of Dokugumon. The Dokugumon then trapped the team and brought them into the abyss of the city where their lord MetalPhantomon resides. He casts the humans into a deep world of painful memories. After being shown his deepest nightmare, Touma overcame it and he developed a new power that allows Gaogamon to further evolved into MachGaogamon.