Batman Unlimited: Mechs vs. Mutants

After freeing helpers in Arkham, Freeze and Penguin freeze down Gotham City and attack with huge monsters. Batman responds, helped by other heroes.
Mr. Freeze turns Killer Croc and Bane into super-sized monsters, and they bash their way through downtown Gotham until the Caped Crusader and his team of heroes join the fight in their giant robot mechs.