The Wonderland Gang

The Wonderland Gang is a gang of criminals in Gotham City, which consists of the Tweed Brothers and Jervis Tetch, the latter whom was brainwashed by the brothers to serve as their leader and pawn. As their name suggests, they are inspired by the works of Lewis Carroll, primarily Alice's Adventures in Wonderland.

History
Thanks to Jervis Tetch's brainwashing over ten years prior, the Tweed Brothers became delusional (with no help due to their time inside Arkham Asylum), and began to fully embrace their roles as Tweedleedum and Tweedledee. After escaping from Arkham Asylum, they formed their own criminal gang which takes themes from Alice in Wonderland, appropriately calling themselves "The Wonderland Gang". Deciding to get revenge on Tetch for what he did to them all those years ago, they kidnap and brainwash him with his own sophisticated brainwashing technology, forcing him to act as their leader and pawn to the gang. Tetch then leads them on a series of violent and almost fatal robberies across Gotham City, which forces Commissioner Gordon to enlist on the help of Batman.

When the brainwashing starts to wear off on Tetch, he starts to grieve for the loss of his late sister Alice, so kidnaps another girl named Alice Young to serve as a replacement at his tea parties. Whilst this disturbs the Tweeds, they decide to keep up the act until they are finished with their work and can properly finish off Tetch.

Batman and Gordon manage to apprehend the Tweed brothers, but before they can reach Tetch they find that he has already killed off Alice, although he claims that she is "asleep". All three of them are sent back to Arkham Asylum, and before Tetch is put into isolation he gets his own back on the Tweeds by leaving a hypnotic clock in their cell, which brainwashes them into carrying out a bloody brawl on each other.

Season 6

 * "The Wonderland Family"