The Gorge of Deception!

Episode 15:
As they wander further into the Digital World, the DATS stumble upon a ghost city which is home to a nest of Dokugumon. Without warning, the spider Digimon quickly trap the DATS and their partner Digimon, dragging them all into the depths below where their lord MetalPhantomon dwells. He casts the DATS into a world of endless nightmares and despair where their greatest fears take shape. In Marcus's nightmare, a Drimogemon was carrying away his sister, Kristy. Marcus tried to rescue her, but a Numemon got in the way. After Marcus punched it, it multiplied, forcing Marcus to punch it again and again. Marcus went after Kristy again, but was trapped by the Numemon, allowing the Drimogemon to escape. In Yoshi's nightmare, she found a younger self of her, telling that she hated her family, that made Yoshi cry for sorrow. In Thomas's dream, he was in the town that he lived with his mother years ago. He remembered the memories of the happy times with his mother. He remembered the tragedy of his mother's death. Thomas tried to stop his mother, but she couldn't hear him. As the younger Thomas and his mother were going to a festival, a speeding truck came by and accidentally killed his mother. Thomas, now what has happened, felt sorrow in his heart. After reliving the painful memory about his mother, Thomas' DNA awakens, granting Gaomon the power to digivolve into his Ultimate form, MachGaogamon. MachGaogamon defeats MetalPhantomon, and the DATS team escape from the gorge, only to find Yoshi has passed out.