Times the Candy Mare has canonically been defeated, by whom, and how in chronological order:
The Most Horrible Hearth's Warming EVER: A Candy Mare Tale - Princess Luna(Survived) - destroyed her candy ghoul army, put her in a coma, and dismembered her, eventually sealed in multiple statues so she could not regenerate
Always a classic monster!
Candy needs more love, and flesh, let's not forget the flesh. Don't want her getting so hungry she goes Candy Kaiju on our asses.