The Frost Legion is a Hardmode event that can be summoned by using a Snow Globe. It is similar to the Goblin Army in the way that it arrives. When a player uses a Snow Globe (which can only be acquired, legitimately, in hardmode), a message that says "Frost Legion is Approaching from the West/East" will appear on the bottom of the screen. The Snowman Gangsta, Mister Stabby and Snow Balla are the monsters in the Legion. They always drop Snow Blocks no matter what.
Upon defeating the legion, Santa will move into an empty house and sell the Santa Outfit and Holiday Lights. However, after January 1, whenever Santa spawns he is immediately slain, effectively removing him from the game.
The Frost Legion are somewhat more difficult to kill than the Goblin Army. However, their lack of Sorcerer alternatives makes them easy to kill with ranged gear. Before 1.2 this was the hardest invasion in the game.
- A good strategy is to barricade yourself in a small area with a hole for ranged weapons (Hardmode items such as the Flamethrower and Cursed Flames are effective, but arrows are also appropriate.) When using this technique, the only thing you need to fear are the Gangsta's bullets. Also, the Ballas' snowballs may clog the range hole; however, this is easily remedied using a Pickaxe, Drill or Drax.
- Snowmen are not able to go down wooden platforms, but are usually jumping about and are able to climb up in this way.
- They are unable to open doors, and they often lock themselves out by shooting snowballs which turn into Snow Blocks upon collision with another block.
- All snowmen are immune to "Cursed Inferno" and "On Fire!" debuffs.
- As of January 1, the player is unable to get any snow globes or presents until the next Christmas, December 15 - 31 of the following year, otherwise the player should resort to a save file with some snow globes obtained during December or by changing the system clock.
- in the 1.3 update, they will have a "new member"
- Added to the game.