The Demon Bat was intended to be a boss in the 2017 video game Cuphead. He was a large black and red bat that was likely intended to be one of The Devil's minions that tries to kill Cuphead and Mugman.
Little is known about the Demon Bat, other than he would have been fought in a Hell-like environment and would have used a variety of attack where he would swoop down at the player, summon smaller bat minions, howl, launch pentagram projectiles, and transform into a giant wolf.
It is unknown why the Demon Bat was unused, though it may be that the boss was scrapped so its attacks could be reused for other bosses or even just time restrictions. Despite being cut, the boss was featured in the E3 2015 trailer, though he was never seen again.