HEROINE POSSESSION BY ALIEN PARASITE

Young Justice  SEASON 1 - EPISODE 26   -  Red Arrow who was brainwashed into using the evil Starro parasite to gain control of the entire Justice League. A possessed mind-controlled Batman authorizes Vandal Savage's entry into the Watchtower. Another heroine fights and resists, & tries to trick Vandal Savage, but is taken over by the alien parasite, & becomes one of them.... (  http://www.tv.com/shows/young-justice/auld-acquaintance-2428714/  )