User blog comment:SilverHexxitFights/Frost Moon vs. Pumpkin Moon/@comment-4661596-20131221134804/@comment-10343067-20131227142433

No matter how great arena you build for it, Santank is not boss of the frost moon. It is the Ice Queen.

My arena for both moons is just flat snow biome (to get the key) with wooden platforms dozen blocks above. And with heart laterns, campfires and water candles on every half screens.