I've been meaning to Dino-fy a hoodie like this for months, but I've been a bit hesitant. I didn't want to mutilate a perfectly good hoodie beyond repair!
I ended up using my red one, which anyone who knows me in real life has probably seen at least a dozen times. It has definitely seen a good amount of wear in its time...
I used splotchy dyed fabric. The other side looks completely different. (Oh, the thrills I'll have wearing this!)
Here's the obligatory 'ZOMG! I'MA DINOSAUR LOLZ!' shot: