Ben 10: Alien Force
The team rescues a young man named Tyler, who stole the Oscillator Key for the Highbreed’s hyperspace gateway from Los Soledad. He crashed the truck and suffered memory loss as he escaped. After being almost captured by the DNAliens in a small town, the team saves him and are forced to race the DNAliens to track down the device, resulting in a battle. The team is victorious, but they discover that Tyler is actually a DNAlien, having managed to resist the Xenocyte controlling him, and only looked human through the use of an ID Mask.