Slow down, Justin Bieber and Lil Twist. The two former child stars, now age 18 and 19, have had quite a 2013 so far. On New Year's Day, Twist was allegedly driving Bieber's Ferrari when they were pulled over for speeding; a paparazzo who tried to take a picture of the stop was struck by a car and killed. That very night, the two friends were photographed at a hotel party in L.A. smoking weed. It's a big blow to the two teen idols' formerly clean-cut images, but more importantly, it could be the first sign of the same problems that have plagued countless other child stars in adulthood. Here, as a cautionary tale for Twist and Biebz, we take a look at past young music stars gone bad.