First appearance of Black Mask (voiced by James Remar).
WILHELM SCREAM: When Robin hits one of Black Mask's henchmen when falling down onto him, the henchman emits the scream.
When Batgirl pulls a lock pick out of the heel of her boot she says "These boots are made for more than just walking" is a reference to the Nancy Sinatra song "These Boots Are Made for Walkin."