1x49 - G.I. Joe: A Real American Hero

Cobra makes a generous donation to the Joes' toy drive: a battalion of Cobra troops, miniaturized to look like toys. Once inside Joe Headquarters, the Cobra forces sabotage the defenses, open the gates, and let the rest of the Cobra forces inside. The Joes have to use Cobra's vehicles to stop Cobra's attack on the city using the Joe's own vehicles.