The Lightyear Factor (S01E30)
Zurg stumbles into a parallel universe where an evil version of Buzz has seized control of the cosmos. This sinister Buzz captures the heroic Buzz and confines him to this alternate dimension while plotting to take over Star Command. Meanwhile, Buzz's loyal friends venture into Zurg's Dreadnaught, believing their comrade has lost his mind, but they end up getting captured themselves. As the good Buzz dodges the evil versions of Mira and Booster, he finds unexpected help from the alternate Nebula, who reveals the alliance between Evil Buzz and Zurg. Together, they work to thwart their foes. Eventually, Team Lightyear is rescued, Star Command is saved, the Dreadnaught is destroyed, and Zurg and his minions escape, leaving Evil Buzz adrift in space, plotting his return in "Sunquake."