From my testing, when struck with a weapon, Batty will recoil (meaning he is a physical entity), give a single orb of juice (though it currently does not make the player's Juice Meter go up), and his health bar will appear on the top of the screen. He's similar to the Koaladog: he takes up space, can be struck, and has an unchangeable health bar.
Batty's event is triggered when the player enters the Graveyard and increases their Juice Meter above 300.
When I tried following him, he ended up outpacing me and I lost sight of him.