A$AP Rocky as William King The rapper – who is currently dating Rihanna — portrays a character named William King, a neighbourhood kid who is charged for robbery and murder alongside Steve. Prior to his role in Monster, Rocky has only had two other roles where he didn't play himself; he was Dom in 2015's Dope and voiced Bodega Cat 2 in the Animals. TV series. Image Source: Getty / Jeff Spicer/BFC