This is a lost episode of Season 1, that came right after episode 3. In this episode, AGK fights 3 enemies.
They're Waluigi, Obunga, and Rodrick Parkinson.
The Whispering Squash also ends up being there and keeping an eye out for AGK.
AGK exits the "BackRooms"
As Episode 2.5 came along, it concluded a connection to this episode. Error Weegee was the cause of AGK being in this area.