Underground Ice castles

Rare ice castle structure that can generate in ice caves with multiple rooms with good loot in them such as ice- and snowballs and other ice/ cold themed loot. New ice trims and -music discs themed after the new ice caves. The ice castle would also have a strong boss spawning naturally inside, throwing freezing potions or ice balls at the player while also spawning ice zombies and strays as a way of defending itself. Once defeated it will drop ice balls freezing potions and possibly even a new music disc or armor trims.