I stumbled upon this today. Very interesting!
https://www.youtube.com/watch?v=7VZ1tUgzjjo
Audio info: source recorded off of phone while playback took place. I'm told the inaudible audio was deleted from the original file as it was mostly feedback. Available audible audio has part of the described scene below. Full description of scene that was given is as follows:
The Joker has a deck of cards in one hand. In the other hand is a long knife. His arm is around a woman's neck holding her from a short distance of Batman.
Batman: Drop the knife! Let her go...
Joker drops the knife, but still holds onto the woman. In his other hand, he shoots all of the cards from his deck out of his hand... except for one card.
Batman (cautiously STOPS walking towards Joker): You're not playing with a full deck.
Joker: The joker's... always...
Joker let's the woman go, she starts to run away. Batman looks at him, and then looks at the woman running away. Joker throws the card and it looks to be heading towards her neck. Batman then runs towards her and throws a batarang. A closeup of her head and neck is shown. The batarang is just splicing/changing direction of the joker card as the shot ends (presuming he saves her). Next, Batman turns to where the Joker was and he has vanished. All that is heard is a maniacal laugh and the word "
wild..."
Speculation: The woman might be Harley. It could be a setup working together to take down Batman.