This is a tribute to Warp Darkmatter, Buzz Lightyear's former friend and partner, who was secretly working for Evil Emperor Zurg since his time at Star Command's academy and later on faked his death and became known as Agent Z for a short period of time and became a recurring enemy of Buzz Lightyear and his team.
Clips from:
Buzz Lightyear of Star Command: The Adventure Begins
Buzz Lightyear of Star Command
Song: Dead to Me by Awake at Last