Megas XLR (Xtra Large Robot) is a giant robot sent to New Jersey to keep it out of the hands of the Glorft. It is owned by Coop Cooplowski.

Megas was originally a prototype giant robot built by the Glorft to be used against humanity. Megas was stolen by the human resistance sometime around the year 3037 and modified by them to be used to help humanity. The resistance intends to send Megas back in time to prevent the Glorft from defeating humanity and conquering the earth. However, before Megas can be sent back in time, the Glorft attack the resistance base. During the battle, Megas suffers a direct hit to the head, destabilizing its time drive and causing it to become lost in the past. Megas lands in a junkyard in New Jersey and stays there until Coop Cooplowski buys it in 2004 for $2. Coop modifies the robot to suit his own tastes, including substituting a car as a replacement head and manufacturing new controls from the controllers of various video game series. Coop gave the rebuilt war machine the name XLR.

Megas is followed back in time by Commander Kiva of the human resistance and the Glorft. Kiva originally intends to reclaim Megas from Coop and return with it to her own time, but discovers that she can't pilot the robot after all of Coop's modifications. After witnessing Coop defeat a group of Glorft Mecha, Kiva decides to stay in the past and help Coop instead.