Enfant Terrible
Enfant Terrible is a witch appearing in Puella Magi Tart Magica. She is the Witch form of Lapin (Link). Her first appearance is in the (X) chapter of Tart Magica. After her defeat, it is revealed that she can turn back into Lapin after her defeat. Enfant Terrible also appears in Magia Record as Lapin's Doppel.
In Tart Magica
The Weeping Hare Witch with a sadistic nature. Her special ability allows her to transform back into a magical girl at her death.
In Magia Record
"The Doppel of sadism. Its form is a weeping hare. The master of this emotion holds feelings of utter brutality in her heart. It may appear to be an adorable rabbit, but one must take absolute care not to lower their guard near it. In reality, it’s the exact opposite of the impression its appearance may give off. Should one be captured by it, they will be overwhelmed as if caught in the fangs of a wild beast, then innocently, playfully, and most cruelly tormented. Accompanied all the while by its pure and terrifying laughter, which resounds far and wide… If one meets this fate, the only option left is to accept the fact that your luck has run out."