19-year old Aaron Clark. Current IFBB pro, formerly from our forum:
At the time, he said he'd only done a 1 month prohormone cycle, benched 315 for reps, and squatted 425 for reps.
As for the what and how, like Yogi said... add lotsa muscle, drop fat. At the time of that pic, Aaron said he was 2 and a half years and gained about 65 pounds in that timeframe. Most teens don't do that (the consistency or the weight gain).