Deerclops

The Deerclops is a pre-Hardmode boss. It is one of the final bosses a player may encounter during pre-Hardmode.

Summoning
The Deerclops can be summoned using a Deer Thing at any time of day as long as the player is in the Snow biome. It also spawns naturally at midnight during a Blizzard.

There are no prerequisite bosses that are required to be defeated in order to summon this boss, however, the Deerclops' strength may warrant waiting until after defeating the Eater of Worlds or Brain of Cthulhu before fighting it.

Behavior
The Deerclops has three attacks:
 * Summoning a wave of ice spikes from the ground
 * Throwing chunks of ice into the air
 * Summoning damaging nightmare hands that chase the player.

The Deerclops its self is invincible unless the player is within a certain radius of it.

When far from the player, the Deerclops can pass through blocks, but otherwise remains on level ground.

Trivia

 * The Deerclops is the only boss in Terraria to not despawn after killing the player.
 * The Deerclops is one of 3 boss fights that consists of a single destructible entity, the other being the Empress of Light, & Lunatic Cultist
 * All other boss fights have either multiple bosses, multiple segments or boss minions that play a part in their boss fights.
 * The Deerclops is the first non-event crossover boss, as well as the first non-event pre-Hardmode crossover boss.
 * Deerclops is one of 5 Bosses with exclusive boss music. The others include Queen Slime, Plantera, Empress of Light, & Queen Bee.