She stood up for a good cause, once, and for that she was punished for it. Her fate wouldve been death if it were not for Rainbow Dash begging for mercy, although.. maybe death wouldve been better than this.

She is cursed by Nightmare herself, a vampire bat almost completely feral with only a hint of recognition of its former self.

She is a hungry and violent creature now

She is the protector of the forest and its creatures