The Nindroid MechDragon was a huge mechanical dragon originally based on the Digital Overlord's former dragon form first introduced in the episode The Art of the Silent Fist. Made by Cyrus Borg on the Overlord's order during the Nindroid Conflict, it was sent out to kidnap Lloyd and take his Golden Power, as it was hunting down both him and his father Sensei Garmadon by the riverside. However, the two were able to escape its clutches while in Nya's car and it was then put down by the other Ninjas after they shut down New Ninjago City's electrical power plant, depriving it of its power and causing it to collapse to the ground.
However, it was not the end of the MechDragon as the Overlord then used it the second time after getting expelled from Borg and a Nindroid as his third vessel in The Curse of the Golden Master, using the Dragon's Electrocobrai energy as a new life source. After striking an alliance with Pythor P. Chumsworth, the Overlord proceeded to capture Lloyd which he succeeded in Enter the Digiverse, where he then held him hostage inside the MechDragon's body in order to prevent the other Ninjas from saving him while trying to drain his powers from him. This unfortunately backfired when the Ninjas rebooted the Digiverse, which severed his connection to the MechDragon and has the controller gone missing. Lloyd got out of the mech on time as it crashed into the ocean, taking the Overlord in his incomplete new form with it.
It was last seen in Codename: Arcturus where Chumsworth and the Nindroids tried to retrieve it from the ocean using balloons.
During the boss battle against Lord Vortech in 1885 Hill Valley while he was in his falcon form, Batman, Gandalf, and Wyldstyle use the Locate Keystone to summon the Nindriod MechDragon to combat him. While doing so, it sends both of them down to the ground by slamming themselves into the ground, destroying itself and injuring Vortech in the process.