Justice League
Ben voiced the DC comic book character Bartholomew Aloysius Lash, known to friends as Bat Lash, in an episode of Justice League Unlimited in 2005.
The episode is season 01, episode 12, The Once and Future Thing: Weird Western Tales, Part 1. You can read a full synopsis of the episode at the DC Animated Universe Wiki and a bio of Bat Lash at DCAU Resources.
Amazon has the episode in HD available for download for $2.99.