Joker: One Operation Joker Vol. 1

During a fight with The Joker, Batman falls into a chemical vat that somehow turns him into a baby. Who is going to take care and help raise baby Batman? The Joker, that's who. Written by Satoshi Miyagawa (Uchuu Senkan Tiramisù) and illustrated by Keisuke Gotou, this manga finds Batman transformed into a baby following an accidental fall into the same vat of chemicals that turned the Joker into his evil self. Immediately after accident, the Joker finds himself lost without his arch-nemesis and takes it upon himself to raise baby Bruce Wayne. However, the Joker finds fatherhood to be a lot more difficult than he initially thought.