Scarecrow

Jonathan Crane is a former psychiatrist at Arkham Asylum turned criminal mastermind. Jonathan had always been fascinated with fear, due to being locked in a church by his overly religious and abusive grandmother where he was attacked by a number of crows. As he grew older, he was bullied for his scrawny appearance and poor choice of clothes. After Harleen Quinzel ran off with The Joker, Jonathan was brought in to replace her by the Asylum's owner, Hugo Strange. Jonathan immediately took advantage of his new position as a psychiatrist to conduct experiments on the patients he was "treating". He began developing toxins that could make his patients see what they feared after finding out their greatest fears. He made them drink it and they began hallucinating. One of his patients said their greatest fear was a scarecrow, and so Crane began creating a mask. Hugo Strange then asked Crane about what he was doing with his patients, to which Crane replied nothing. But Hugo saw the experimental results of the hallucinogenic drug.

Crane put on a scarecrow mask to scare his patient, but Hugo saw this and fired him. However Hugo actually fired Jonathan so that he could take his drug and continue to work on it. Jonathan eventually found out about this. He created a scarecrow costume and attacked Hugo, spraying his fear toxin all around Hugo. Crane then dubbed himself Scarecrow. Scarecrow began to terrorize Gotham City by releasing his fear toxin. Batman eventually caught word of Scarecrow, however he was sprayed with the toxin and began hallucinating.

Alfred managed to develop an antidote, and Batman poured it into Gotham's water supply and stopped Scarecrow. Over the years, Scarecrow and Batman have faced off many times and he has since become a founding member of Batman's rogue's gallery. Scarecrow and Batman have fought for many years.