After Kamiko's soul is transferred to your body you are directed to go to the "Wang Cave" as the next part of the mission. After entering the building immediately go into the backstage area behind the drum set, you will see text on the wall that says "Pay no attention to the man behind the curtain!". While facing this text turn ninety degrees to the right and walk through the closed door in front of you. You will reach a hidden basement area with a large portrait of the Flying Wild Hog Development team along with several tags from the staff.