Who is Batman's fiercest foe?

Joker (Heath Ledger), The Dark Knight

Riddler (Jim Carrey), Batman Forever

Mr. Freeze (Arnold Schwarzenegger), Batman & Robin

Penguin (Danny DeVito), Batman Returns

Catwoman (Michelle Pfeiffer), Batman Returns

Poison Ivy (Uma Thurman), Batman & Robin

Harvey Dent (Aaron Eckhart), The Dark Knight

The Scarecrow (Cillian Murphy), Batman Begins