B:TB&tB season 3 episode 8
B:TB&tB season 3 episode 8 "Triumvirate of Terror!" Directed by Michael Goguen.
The "Hall of Justice" had already appeared in The Brave and Bold:
so it was only fair that the "Legion of Doom" made an appearance before the series had ended.
"Batman: The Brave and the Bold" ™Warner Bros. Animation.