In the videogame Arkham Asylum, the Joker get captured by Batman and sent into Arkham Asylum. But this is all a trap, as the Joker planned to take over Arkham Asylum and use its infamous inmates to fight Batman.
At some point, Batman needs supplies and decides to enter an annex of the Batcave that was built in case someone went wrong in Arkham (crazily prepared vigilante!).
Of course, this is really convenient in the setting of the game, since it allows the appearance of the Batcave without having Batman leave Arkham's island.
But, as someone who mostly knows about Batman through the movies and the animated series, this really surprised me.
Does Batman have a Batcave under Arkham Asylum in some version of comics?