The van that Joker and Harley use is the same van that 'Team Penguin' used in the episode of the same name. It only has some minor modifications by Joker like some stickers with his face.
Robin: (about Wrath and Scorn) Great. Now, the guys in hero suits are shooting at us.
Robin: (about Wrath and Scorn) So, what do you think? Alternate versions of us from a parallel universe? Or maybe our matter anti-matter twins?
Batman: You've been reading too many comic books.
Robin: (after Wrath and Scorn are knocked off their bikes) "W" and "S" - "Wipe-out" and "Sudden Stop"!
Wrath: If I go to jail, I'll tell everyone who you are! You'll be a target the rest of your life! But I swear, I'll never tell a soul if you just let us go!
Batman: But that really would destroy everything I am.
Daryl Sabara (Scorn) previously voiced Harris, Dick Grayson's lab partner in "Riddler's Revenge".
Killer Croc references the events of "Team Penguin," when he, Penguin, Joker, Scarface and Wesker are gathered together by Wrath.
Wrath is the third villain to learn the Batman's identity (the other two being Dracula and D.A.V.E.).
Harley appears but has no dialogue.
The Joker, Penguin, The Ventriloquist & Scarface, and Killer Croc return.
Wrath and Scorn are introduced.