A robot that is too complex for Viceroy to control, so he installs it's control panel in the local arcade for experienced gamers.
Coincidentally it was found by Howard, who was presently in a feud with Randy over who could win the most games. Randy was forced to go fight and shocked to discover Jack Hammer was real. Howard controling him, thought it was all a game.
As such the city was being destroyed, to big and powerful to stop. Randy tried to tell Howard, but thinking he was trying to trick him to win Howard didn't believe him. He even managed to capture Randy. Breaking out Randy realised the only way to stop him was to let Howard win, so he rolled with the blows until Howard got a big enough score to win. Afterwards Howard had Jack Hammer jumped off a cliff, destroying the robot.