LOS ANGELES — Last week, blogs reported that an 18-year-old graffiti artist named Skull Phone hacked into ClearChannel digital billboards in the LA area and posted his trademark tag. Some of those blogs have now posted that the entire stunt was a hoax.According to Curbed Los Angeles: Last Thursday, images of a neon skull were spotted on billboards all over the city, leading many to believe the street artist had hacked his way into Clear Channel’s billboards. A source confirms what we already suspected: Graffiti artist Skull Phone paid Clear Channel an undisclosed sum for one-day Los Angeles-wide “ads.”