become one?

 Batman Villains  Catwoman  Dr. Jonathan Crane 'Scarecrow'  Harley Quinn  Joker and Batman  Joker and Harley  Poison Ivy  Suicide Squad 

"Madness is the emergency exit. You can just step outside, and close the door on all those dreadful things that happened. You can lock them away... forever." - The Joker, The Killing Joke