Snake Boxer 5 Cobra Mode
On the Snake Boxer 5 title screen press the following combination and you will be using a cobra rather than "Boxer Joe".
up, up, down, up, plus - To unlocks Cobra Mode on SB5
To find the secret shirt, while in the photo booth, aim your Wii remote around/at the top of the light closest to The Cheat. Press the A button when the cursor changes and hold and drag it over to Strong Bad to wear it.