Megadramon is a snakelike dragonlike Digimon with sharp claws. He is Ultimate level. He appeared in the episode Blame it on Ryo.
When Rika set a clock right, this stopped the gears from moving, releasing him from his prison below the area. Renamon digivolved to Kyubimon to fight him, but he gained the upper hand and was about to destroy her when Cyberdramon attacked him with Desolation Claw. He was about to destroy Megadramon when Ryo stopped him, as he was not the opponent they were searching for. Megadramon returned to his prison, which was then sealed when Ryo got the gears moving again.
It is unknown whether he was killed by the D-Reaper during its invasion of the digital world.