Park Sang-hyun (Korean: 박상현; born October 7, 1990)[1][2][8] better known by his stage name Thunder (Hangul: 천둥; RR: Cheondung), is a South Korean singer, songwriter, actor and model. He is a former member of South Korean boy band MBLAQ. On December 16, 2014, it was announced that he had departed from the group to focus on studying music.[9] He signed with Mystic Entertainment's music label APOP on February 11, 2015[3][4][5][6][7] and released his debut extended play on December 7, 2016.