Batman is always the baddest guy in the room until he meets an alternate version of himself that’s a real nightmare. The caped crusader travels to Earth-43 AKA Nightmare World where he encounters a vampire Batman!
The demonic duo duke it out in Infinite Crisis: Fight for the Multiverse #31. Nightmare Robin, a vampire version of his son Damian, warns that he can’t beat Nightmare Batman because no one ever has. Batman confidently responds, “Then no one’s tried hard enough.”
Not even the combined might of Batman, Nightmare Robin and Hawkgirl can subdue the creature. Batman tells them to stay back and uses his grapple gun to bind the beast but it effortlessly snaps the cable. It lunges forward and easily overpowers him. Nightmare Robin saves Batman before the creature can feed on him. Batman reprimands Robin for interfering but it’s clearly more about his pride.
They retreat after they acquire the intel they came for. Batman calls the battle “redundant.” Another way to look at it is that it’s redundant because regardless of the outcome of the fight, Batman wins.