Game Over - S3.E6

The Tennysons stay in as it rains outside, and Ben plays a video game to pass the time by. When Gwen decides to join in, Ben is jealous of how she's a far superior player. Instead, Ben decides to transform to Upgrade, and merges with the game console. Gwen makes an attempt at shaking him off, but suddenly, a lightning strike causes them to transfer into the video game itself. The only way Ben can use the Omnitrix is to find coins with the different aliens on it. To get out, they must find the Upgrade coin before an evil being uses it to escape into the real world.