Pyo Ji-hoon (born February 2, 1993), better known by his stage name P.O, is a South Korean rapper. He is a member of the South Korean boy group Block B and its sub-unit Bastarz. Pyo Ji-hoon (born February 2, 1993), better known by his stage name P.O, is a South Korean rapper. He is a member of the South Korean boy group Block B and its sub-unit Bastarz.