Johnny Test - Sonic Johnny // The Return of Johnny X

Johnny disrupts the Science Expo, where Bling-Bling Boy introduces a dangerous reptilian pet called the Repto-Slicer. The creature escapes, forcing Johnny and his sisters to activate Johnny X and his powers to stop the rampaging beast.

After several failed attempts to stop the Repto-Slicer, the group learns its weakness. Johnny uses a ball to train the creature, eventually turning the destructive machine into a well-behaved pet that helps the family prepare dinner.

Frustrated with his slow scooter, Johnny takes his sisters' experimental hypersonic scooter for a test ride, ignoring warnings about the Mach 9 setting. His speed triggers an accident that propels him and Dukey into a dystopian, desolate future.

Johnny and Dukey are branded as wanted fugitives in a ruined future caused by their time-travel incident. They track down their elderly sisters in a high-security facility to find a way to repair the scooter and return to the past.

With the help of their elderly sisters and customized high-tech wheelchairs, Johnny and Dukey escape the robo-police and return to the lab to reverse the time effect. Johnny successfully returns to his own time and declines the offer to test the dangerous scooter, preventing the future disaster.