"I know being a teenage vigilante has it's risks, Dear Diary. But RATS?" -Stephanie Brown
Real name: Otis Flannegan
The Ratcatcher escaped Blackgate prison along with Stephanie's father in Batman: Huntress/Spoiler: Blunt Trauma. When Spoiler caught up to him in the mall, the Ratcatcher actually released his "friends" on Stephanie under The Cluemaster's orders. She managed to avoid the rats by seeking high ground while Arthur and Flannegan congratulated themselves and told each other they should work together again. Stephanie interrupted this conversation by kicking both of them in the back of the head, knocking Otis Flannegan out to be picked up by the cops.
Learn more about the Ratcatcher here