Icicole, Messenger of the Ice King

Icicole, Messenger of the Ice King (phew, that was long), is a Hardmode Boss. He is intended to be fought after the WoF but before the Mechanicals. After the Wall is defeated, there's a 1/4 chance every day at 4:30 AM that a message will pop in the chat: The eternal winter glows furiously... That signifies that you will have to travel to the Snow Biome. If not within 45 seconds, he will become enraged when he spawns, quintupling his attack and defense. He can also be summoned using a Ice Flute, and has 10,000 (18,000 in expert) and 19 Defense (24 in expert).

Phase 1
In the 1st phase, he will fly around, hurling icicles at you that deal 23 (40) damage each with a half second interval. He will also sometimes sit in one place, hurling waves of ice orbs in random directions. These do 40 (70) damage. He also spawns a square once in this phase that repeatedly spams ice squares towards the player that deal 31 damage. The spawner can't be killed, it just disappears once Phase 1 is done. (not in expert). Speaking of which...

Phase 2
Icicole drops to Phase 2 once he drops to 4,000. He now spawns in 2 more squares, although the square from Phase 1 disappears (not in expert mode). The time in between his attacks are halved (quartered in expert mode), and he gains a new attack. He now can spawn a vilethorn projectile that can reach as far as 20 tiles (45 in expert), and he now spawns Snow Spirits.

Phase 3 (Expert Mode Only)
When Icicole drops to 500, he regenerates 5,000 and starts spamming all his attacks except for the ice square one. He now starts spawning in Snow Apparitions instead, and he creates a bullet hell, with gigantic 5 by 15 icicles raining down from the sky and ground.

Drops
Icicole will always drop one of 5 items: In Expert Mode:
 * Glaicer (Melee)
 * Icebreaker (Ranged)
 * Iciflare (Magic)
 * Snowdust Staff (Summoner)
 * Bottomless Snowball Bag (Throwing)
 * Treasure Bag (Icicole, Messenger of the Ice King)
 * Cryo Rune

Aftermath

 * The Wizard will begin to sell Ice Flutes on Waxing and Waning Gibbons.
 * The Dryrad will move in if she has not already.
 * Life Cubes will begin generating in the Snow Biome (But can only be broken after Golem is defeated).

Achivements
Subzero Salvation: Free the Messenger from his curse. (Defeat Icicole.)