Top Ten DC Comics Villains that Broke Into the BatcaveBatman surely has a hard time keeping his lair secured, but here's a list of goon that have breached in the cave.
The Top Ten DC Comics Villains that Broke Into the Batcave
Things didn't go well for Alfred when Joker breaks in and chops old Jeeves' hand off with a meat cleaver. Joker appreciates how his signature card was kept in the Batcave. - TechnicallyIDoComics
This was a crossover between Marvel and DC and Bullseye did fought Batman in his Batcave. - TechnicallyIDoComics
Well he did came from Marvel, not DC. Surly he did broke into the cave in the crossover.