I'm pretty sure you all know how hard it is to make a card for a teenage boy, and knowing Matthew, I thought the best way to go was to keep it simple.
Images: skull boyz by Sugar Nellie - I have used a pastel blue promarker to accentuate the shading and doodled the greeting with sakura micron pen
I used WordArt on MS Publisher to make an oversized "16" template, then cut it from Black Magic Core'dinations card. Then embossed in the cuttlebug with the happy birthday folder, and sanded to show the blue colour core.
The card base is grey SU cardstock