The Batman of Zur-En-Arrh
If you are not familiar with the comics, you are probably wondering why the hell Bruce is dressed up in a purple, red, and yellow Batsuit, and brandishing a baseball bat! In the modern continuity, Dr. Simon Hurt and the Black Glove engaged in a long-term campaign to break Batman physically and mentally. At the endgame, Dr. Hurt had activated post-hypnotic trigger, drugged Bruce, and left him an amnesiac in Gotham City.
However, Batman literally plans ahead for every possible contingency. A separate persona deep in his subconscious, designed in case of severe psychological trauma, activates calling himself the Batman of Zur-En-Arrh. This is what happens when Batman goes truly psychotic – or if Batman was pure id & did not have the Bruce Wayne persona to guide him. This Batman is more brave, reckless, and more willing to maim and torture criminals. See exhibit A – the baseball bat. He also sees hallucinations in the form of Bat-Mite who acts as Batman’s moral compass.
Considering how prevalent the motifs of mental trauma, insanity/psychosis, and hallucinations are in Arkham Knight, it would inject a dose of hilarity to have the apparition of Bat-Mite appear beside you as run around Gotham beating up thugs with a baseball bat. Radio transmissions of thugs and the Arkham Knight militia can change to react to the *excuse the term* bat-shit crazy Zur-En-Arrh persona before them.
Quite surprisingly, a YouTube video posted by MrJAG showcases Arkham Knight gameplay footage featuring the Batman of Zur-En-Arrh – although, additional research could not ascertain whether this was a mod or a future skin. In either case, this would truly make for the most terrifying and hilarious alternate Batsuit to date.