Eye of Cthulhu

. "You feel an evil presence watching you."

The Eye of Cthulhu is the first Boss a player will generally encounter, as it spawns automatically when a relatively early level of game advancement is achieved. It is considered the easiest Boss in the game, though still presents a challenge to newer players. The Eye of Cthulhu can also be summoned manually by using a Suspicious Looking Eye at Night.

The Eye of Cthulhu has a 1 in 3 chance of spawning each night once the following conditions are met:


 * At least one player in the world has at least 200 life.
 * At least one player has more than 10 defense.
 * At least three NPCs are spawned (not counting the Old Man at the Dungeon).
 * The Eye of Cthulhu has not yet been defeated in the current world.

The Eye of Cthulhu's approach is signaled with the message: "You feel an evil presence watching you." Within 20-40 seconds of this message, the Eye of Cthulhu will appear and begin attacking the player. If the Eye is not defeated by dawn, or if all players die or run away while fighting it, it flies away and despawns. If this happens and the Eye has not yet been defeated at least once within the current World, the Eye continues to have a 1 in 3 chance of returning on subsequent nights. Once defeated, the Eye will not return again unless summoned by a player. Note that if the player activates the Magic Mirror the Eye will not follow it and the player will have to wait for one more night.

Behavior
The Eye of Cthulhu looks like an enormous Demon Eye, but it behaves quite differently, and can travel through all blocks. It hovers briefly and then tries to ram the player three times. In its first form, it spawns Servants of Cthulhu while hovering.

After the Eye of Cthulhu reaches half (1400 HP) of its health, it will transform into its second form, which is faster and deals more damage, but its defense is dropped all the way down to 0 and no longer spawns Servants of Cthulhu.

While the Eye of Cthulhu drops Demonite Ore, it will not drop Shadow Scales. Some Demonite items (such as Shadow armor and the Nightmare Pickaxe) cannot be crafted without Shadow Scales, which are dropped by the Eater of Worlds.

Likewise in a world with the Crimson instead of Corruption, the Eye of Cthulhu will drop Crimtane Ore but not Tissue Samples, which are needed in some recipes.

Tips

 * Farming the Eye of Cthulhu is one of the most effective ways of making money prior to Hardmode, second only to the Eater of Worlds in one-time drop value. Its coin drop, combined with selling its item drops, will yield an average of 7 in total each time. Mid- to end-game armor and weapons make the fight very easy.
 * When the Eye of Cthulu is changing into its second form, it stops moving and spins for a couple seconds giving you a chance to deal massive damage.
 * It's beneficial to make an arena that consists of multiple layers of wood platforms, as it is with most bosses.
 * Using rope systems in your arena can help you dodge vertically, especially on the second stage. However, due to the dexterity required to maneuver between rope and platforms (you need a 1 space buffer between any platforms and the rope for maximum speed) and the extremely slow speed of horizontal rope, it is not recommended for either new players or players who are generally less adept at quickly maneuvering the controls to use this method.
 * the best early pre-mode weapon is the Shuriken which can be bought from the Merchant for 20 copper coins

Trivia

 * Cthulhu is an entity from the works of writer H.P. Lovecraft, first appearing in his short story The Call of Cthulhu. Cthulhu is described as a slumbering Elder God who will destroy all living things should he ever awaken.
 * Rarely, is the Eye of Cthulhu is spawned in the underground Crimson, he will depart immediately after arriving and drop a mechanical eye. (Needs confirmation if glitch or not)

History
Œil de Cthulhu Eye of Cthulhu Eye of Cthulhu Глаз Ктулху