Prank

Prank (real name: Donnie) is a minor villain in the The Batman episode "The Apprentice". Donnie is a disliked kid at Barbara Gordon's school who thinks of himself as the class clown even if no one thinks so. Fed up of being teased, he goes a comedy club where he catches the Joker's attention.

The Batman
Donnie attended the same middle school as Barbara Gordon aka Batgirl, Batman's sidekick. He was a hated kid there and though he tried to be more popular by cracking unfunny jokes he became even less popular. He later tried doing to the same at a comedy club where he caught the Joker's attention who offered to accept him as his sidekick "Prank". Intrigued and jealous of Batman having the same, he agreed.

After a series of pranks, including hoisting his teacher up to a flagpole, he and the Joker planned a scheme to kill some cops. The plan was foiled by Batman and Batgirl. But, when Joker gained the upper-hand in a fight, it was his turn to follow his footsteps by murdering Batgirl but he couldn't. Joker was infuriated and not amused by his protege's defiance and was about to drop Donnie in a vat of chemicals in his hide-out to complete Donnie's transformation. When Batman and Batgirl saved him, he delivered the final blow to Joker by knocking Joker out with his own flag-gun.