Giant Buford is the main antagonist in the Phineas and Ferb episode, Gaming the System. He was created by Phineas and Ferb when they created an enhanced version of Jump & Duck that allows players to enter the video game. They decided to make a giant version of Buford as the final boss (which made the real Buford pleased until the climax).
When Candace, Phineas, and Ferb were traveling through the video game, they eventually reached the final level. As soon as they entered the final level, the Giant Buford appeared, and attacked Phineas & Ferb. Candace tried to defend her brothers, but lost her hair dryer. Desperate to defeat the final boss, Candace grabbed her life bar and used it as a blunt object. With a swing of the life bar, Giant Buford fell to his "demise", but not before crushing Phineas and Ferb ( though the two survived, due to the two having several lives). After Giant Buford was defeated, Phineas, Ferb, and Candace returned to the real world.
After which, Phineas asked Candace how she previously defeated the final boss, as he also explained that during a final boss, usually the boss returns but stronger. Candace then explained that she didn't. Moments later, the Giant Buford appeared in front of them as the second part of the final boss takes place in the real world. Giant Buford processed to attack the children. The real Buford tried to befriend his giant counterpart, but Giant Buford attacked him, much to Buford's dismay. Moments later, Isabella showed up with a camera, which she uses to take a picture of the Giant Buford, resulting him to dipixelate into her camera, ending his rampage.