At the Snake Boxer 5 title screen, press [Up] [Up] [Down] [Up] S. Boxer Joe will be replaced with a Cobra.Hidden shirt
Enter the photo booth, and have Strong Bad walk off the right side of the screen. Do this a second and third time. On the last time, Strong Bad should now be upside down, walking on the bottom of the booth. Walk to the right, and stay even with the door. Position Strong Bad as far to the back as possible. When in the correct position, a sound will play and Strong Bad will now be wearing a hidden shirt. This must be repeated if you want to wear it again because it will not be placed in the clothing rack when removed.