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.

Spawn
The Eye of Cthulhu can be summoned manually by using a Suspicious Looking Eye at Night. It also has a 1 in 3 chance of spawning automatically each night once the following conditions are met:

Its 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 despawns.
 * At least one player in the world has at least 200 life and more than 10 defense.
 * At least four Town NPCs are acquired.
 * The Eye of Cthulhu has not yet been defeated in the current world.
 * There is one or more blue candles in your home.

Behavior
The Eye of Cthulhu looks like an enormous Demon Eye. Like most bosses, it travels through all blocks.

The Eye hovers briefly and then tries to ram the player three times. In its first form, it spawns mini-eyes called Servants of Cthulhu while hovering.

When it falls below half health (1400), it transforms into its second form, which is faster, deals more damage, and makes more ramming attempts. Its defense, however, drops to 0, and it no longer spawns Servants of Cthulhu.

Tips

 * The Eye of Cthulhu drops Demonite Ore. Most game-advancing Demonite items also require Shadow Scales, which the Eye doesn't drop (Shadow armor, Nightmare Pickaxe), so the Eater of Worlds should be the player's next goal. Likewise in a world with the Crimson instead of Corruption, the Eye of Cthulhu will drop some Crimtane Ore but not any Tissue Samples.
 * 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.
 * Obtaining a Starfury from a Floating Island can greatly increase early/mid game success in besting this foe. Learning to control the falling star mechanic of the Starfury is key in this advantage because that the star does not fall randomly but rather in relation to the player and the cursor.

Strategy

 * 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.
 * It helps to have a ranged weapon, as this makes it easier to hit the Eye of Cthulhu.
 * Having something that allows flight helps by allowing you to get near to the Eye of Cthulhu while it is hovering.
 * Using Shurikens or Throwing Knives against it in the early part of the game can cause a lot of damage rather easily, and the pierce of these items will also kill the Servants of Cthulhu it spawns almost instantly.
 * Summoning the Eye of Cthulhu during a Blood Moon doesn't appear to make the fight any more difficult, and doesn't appear to increase the amount of loot that it should drop.
 * The Eye looks at the player it will follow, which can be helpful information in multiplayer.

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.
 * Sometimes NPCs will mention sensing something evil watching them when you meet the requirements to battle the Eye of Cthulu.


 * This is possibly a reference to the aquabats song "the floating eye of death"

History
Œil de Cthulhu Eye of Cthulhu Eye of Cthulhu Глаз Ктулху 克蘇魯之眼