Jordan Fisher has joined season 7 of as Bart Allen, who also goes by the superhero alias Impulse, ET has learned.Fisher will make his first appearance as Bart/Impulse on The CW superhero drama's landmark 150th episode, which is the season's 17th. He will be a recurring guest star.Bart Allen is the future son of Barry Allen and Iris West-Allen and much like his father, is the fastest teenager on the planet.