The Naljian Destructor is Level 20+ technology that can turn into a robotic version of whatever or whoever it sees. It can even form into one giant combination of everything it has seen. It will do whatever it sees something do.
The Naljian Destructor appears in Busy Box where it is causing havoc everywhere. When Ben went near it, it transformed into a copy of Ben. It even transformed into a copy of Humungousaur when Ben transformed into Humungousaur. The Naljian Destructor even turned into a copy of Spidermonkey when Ben turned into Spidermonkey. When Kevin went near it, it turned into a copy of Kevin, followed by Kevin's mutation after his ID Mask was broken by it. When Gwen went near it to reason with it, it also turned into a copy of Gwen and tried to meditate. It's also evident that it will mimic a move or an attack another will do but in a more mechanical way, for example, it threw pink, metal discs when Gwen threw mana discs and it threw large, red and hot balls for Swampfire's fireballs. It can also look like one person but use another's different powers as seen when it turned into a copy of Octagon Vreedle and used its version of Swampfire's fireballs. Around that time, the Vreedle Brothers arrived identifying it and tried to claim it. As Ben turned into Swampfire, the Naljian Destructor also turned into a copy of Swampfire. It even managed to turn into each of the Vreedle Brothers as they baited it to their side and made off with it. Moments later, the Vreedle Brothers returned stating "He learned that he really likes destroying things" and that it has become too powerful for them to control and left it on Earth. The Naljian Destructor then transforms into an amalgamated version of Humungousaur, Spidermonkey, Swampfire, the Vreedle's weapons, and Kevin, which they then started attacking. During the fight, Ben, Gwen and Kevin managed to find out its weakness is its core.
After Lodestar managed to remove the core, it fell apart. When Ben was about to permanently destroy the core, a cosmic being appeared out of nowhere. She told them that the device was her daughter's toy. She then explained that it was a dangerous weapon to them because their species was too young to properly use the Naljian Destructor. The mother of the child reassembled it and left shortly after, stating that it was clearly marked "Not for children under three million years old."
Ben 10: Alien Force
- Busy Box (first appearance)
- Primus Override