"Mayhem of the Music Meister!" is an episode of the Batman: The Brave and the Bold animated series. The episode features the villainous Music Meister (voiced by Neil Patrick Harris), who uses his power to control people through song to try to take over the world. Written by Mike Jelenic and directed by Ben Jones, the episode premiered on October 23, 2009, the 24th of the first season.
The musical episode, which has been compared to Buffy the Vampire Slayer's "Once More, with Feeling", was generally critically acclaimed and well received by viewers. Unlike other episodes of in this series, this episode does not feature a cold open or teaser at the start.