Question: what are the episodes of crisis on earth x?
Answer: Supergirl, Season 3 Episode 8 (aired on Monday night, 8/7c) Arrow, Season 6 Episode 8 (aired on Monday night, 9/8c) The Flash, Season 4 Episode 8 (airing on Tuesday night, 8/7c) Legends of Tomorrow, Season 3 Episode 8 (airing on Tuesday night, 9/8c)