Hypothema

Hypothema is a Pre-Hardmode boss that must be fought in the snow biome. She is considered a biome-specific boss for the Snow biome.

Spawn
Hypothema does not spawn on her own, and requires the player to summon her with a Chilled Mesh. She can only be summoned while the player is in the snow biome.

Behavior
Hypothema has 3 movement phases: She switches between these attacks periodically, in the described order. Once she has finished the Dashing phase, she loops back up to Hovering and starts again.
 * Hovering slightly above the player
 * Floating around the player
 * Dashing through the player

Attacks

 * Hypothema periodically shoots slightly homing Ice Shards in 8 directions around herself.

In Expert Mode
 * On top of the 8 directional slightly homing shot, Hypothema also shoots a swift moving projectile that homes in on the player much better and faster.
 * Hypothema and all her projectiles inflict Chilled and Frostburn.

Trivia

 * This boss was named after the condition Hypothermia, which involves getting extremely cold.