Hong Seok, a member of the group Pentagon, showed his vengeful on SBS' "Firebird 2020."

In the 71st episode of SBS' daily drama "Firebird 2020," which aired February 1st, Shin Ah-joon (Hong Soo-ah) expressed his intention to separate the relationship between Lee Ji-eun (Hong Soo-ah) and Seo Jung-min (Seo Ha-joon).

In the show, Shin Ah-joon pointed to Lee Ji-eun, saying, "I'm hooked on this lady," to Seo Jung-min (Seo Ha-joon), whom he met in front of the elevator. Shin Ah-joon said, "You don't have a boyfriend, do you? What do you think about me?" asked Lee Ji-eun, who firmly said, "I already love somebody."

In particular, Hong Seok raised viewers' curiosity to the fullest as he predicted a new development of the show as well as a sharp look as deadly as poison.