This may have been done on some server or something , but i was thinking that you could make a new enemy, only for the snow biome, permenantly in the game for PC(or 360). You should try to make a Yeti type creature that can only be found in the snow biome(obviously), the player has to really explore and it would be hard to find them, they could only be found high in mountains or in the middle of nowhere, they wouldn't be an underground creature. They would be extra strong, but in killing it, you would get extra expereince. I just though it would be cool. I'm pretty sure you guys are strict and sticking with the enemys you already have, but i think, done right, an Abominable Snowman type character would be awesome, and decently scary, if you were hunting or traveling at night in the mountains or snow biome, and this thing just jumped out of nowhere! It would be awesome!
Nah, I'd suggest something like an item called 'Magical Snowball' that can be brewed into a 'Potion of Frigidness' (Freezes the user/target in place for 15-20 seconds, it wears off if around fire/in a hot biome). Good idea though!