It is shown as a prototype of a more advanced version of the Foot-Bots. In its first mission, she used it to attack April, who Karai had a particularly bitter vendetta against. Its appearance is extremely similar to Chris Bradford's "Dark Ninja" uniform and is armed with a plasma katana and whip. Karai attempted to use "Chrome Dome" to destroy April, but during the Foot Clan's fight with the Turtles, "Chrome Dome" snatched April away from her duel with Karai instead of killing her as Karai demanded, where it revealed that the Kraang Hive Mind overrode its systems and made it carry out their own bidding - to deliver April to them unharmed because they needed her for their invasion plans. Consequently, "Chrome Dome" came equally into conflict with Karai and the Turtles, and now viewed both sides as its enemy.
Karai became enraged at this and tried to attack "Chrome Dome", which ended up turning the droid against her. "Chrome Dome" easily outmatched Karai and her Foot-Bots and the Shellraiser. During the subsequent battle with the robot, Donatello succeeded in removing a panel on its back and tore out some wires, whereupon "Chrome Dome" lost control of its physical faculties before he was ultimately defeated when Michelangelo drove its own plasma sword through the center of its chest.
Later, Chrome Dome reappeared briefly in "Vengeance is Mine" as a decoy for Shredder in order to capture Karai, who wanted to take revenge on Shredder for his lies and the murder of her mother. This Chrome Dome is destroyed by Karai in her quest for vengeance. Whether it was the same one faced before or not is unclear.
Chrome Dome looks like Chris Bradford in his "Dark Ninja" outfit, but with chrome mechanical upper arms. Since Bradford no longer wears this armor after his mutation, it may have been employed in the robot's construction.
- Despite it being named "Chrome Dome" by Mikey in the show, and official Nick sites use that name, it is for some reason given the name "Dark Ninja Robot" in the credits.
- In "Broken Foot", the Foot-Bots have been upgraded into new versions that are called Elite Footbots that resemble Chrome Dome; the only difference is that they wear metal Kasas on their heads.