Emperor Zurg of the Star Command universe was creating a device to teleport him to Star Command in the blink of an eye, to use it for his entire army. But he got something else. Make it a SOMEONE!!! He got Lightyear Zurg, the one in the movie. He was supremely shocked that Buzz Lightyear became Zurg in that universe and has met an alternate version of Buzz where he didn't become Zurg. Together, they forged an alliance to conquer the entire multiverse because they realize that Buzz Lightyear is everywhere, no matter what world. Now the Buzzes that they have faced have joined forces as well.
