Guide:Eye of Cthulhu strategies

The Eye of Cthulhu is usually the first boss a player will encounter. It has a one in three chance of spawning once a player has met a few base conditions: Having at least 200 health(10 hearts), having at least 10 defense, having three NPCs, and assuming that the player hasn't already defeated the Eye. Since it is so likely to appear preparation is almost vital, especially for newer players. The following are some hints, tips, and strategies to help you defeat it. Note: if you acquire a Suspicious Looking Eye and use it while the screen says, " You feel an evil presence watching you" it is possible to fight two Eyes of Cthulhu at once.

First option for battle
A ranged weapon, Thorns Potion, and at least iron armor is very helpful while battling the Eye of Cthulhu. Try not to use mana items at this stage of game unless you have lots of mana stars. Also, try to use an Ironskin Potion to tank damage. If you have defeated Skeletron (Which is not recommended at this stage of game), use a Muramasa to battle. A recommended weapon to use is a Light's Bane, as it does over 15 damage. A recommended bow is a gold or a tungsten bow, as they are powerful. Use fire arrows, crafted from regular arrows and a torch, to deal extra damage and have a chance of scorching Eye of Cthulhu. If you can, find a Thorn Chakram in a golden chest underground. It will help you in battle.

Terrain preparation
Since this is the first boss you will face, you are limited with items to put in your arena, but campfires would boost your life regeneration. As for the terrain itself, rows of wood platforms will be the best choice. This gives you maximum mobility, especially if you have a cloud in a bottle. Lastly put a nurse close to the arena for some quick healing if you need to. This arena is also be suitable to fight The Destroyer later on however, it will need to be made bigger.

Armor
The best armor to have is gold or platinum armor, but it's not required. Silver or tungsten armor is the easiest to get at this point, and it is a good choice for this fight. Iron or lead armor can be used, but caution must be taken, especially in the second phase, and should only be used if you are a good dodger. Copper, tin, and wood armor don't have enough defense to take the hits of the 2nd phase and should not be used unless you have built a good arena and are a skillful dodger.

Accessories
To help in avoiding the second phase, using some form of jumping aid would definitely be useful, but is not essential. Hermes Boots help by allowing a chance to dodge the second phase's rams. A Cloud in a Bottle, Sandstorm in a Bottle (if your world contains a pyramid), or Blizzard in a Bottle can also aid in avoiding the rams. If you find one, a Band of Regeneration can help speed up life regen, making lasting a longer fight easier. A Panic Necklace is a useful accessory if you have a hard time dodging attacks, and the increase in speed after being hit can make being hit immediately after less likely. A Shackle with a Warding modifier can serve as a good accessory if there is an open accessory slot, and the extra five defense can be used to make up for lower-tier armor, like Iron or Lead. Also, in the mobile version, the Boots of Ostara, which are dropped by Lepus, help a lot. Dynamite would help when in second form because it blows up everything so when it charges, throwing the dynamite will deal a nice amount of damage. If you have defeated the goblin army throw Spiky Balls in a pit and lead the eye through them. It does damage to the Servants of Cthulhu as well.

Weapons
Because this boss summons many minions, weapons with a piercing attack are extremely useful. Shurikens are an effective weapon which can be bought from the Merchant. They will hit up to 4 times, allowing a well aimed shot to kill a Servant and hit the Eye twice - even three times, if it falls back through the boss. 500 or so are more than enough to defeat this boss with relative ease.

A Thorn Chakram is quite effective if you can obtain it before the fight. It can be thrown relatively quickly and it's unique ability to bounce off walls up to 4 times can kill both the boss and it's minions quickly. Also,the poisoned debuff from hitting the eye (occasionally) can sap it's hp making the fight slightly easier.

A Vilethorn is always handy, especially when the Eye is inside of blocks, as it deals constant damage and can be fired through blocks. Other great magic weapons are staffs (preferably a Emerald Staff, Ruby or Diamond Staff), which cause more damage while using less mana. Bows with Jester's or Unholy Arrows are good for their high damage. The former can be found in Chests Underground or crafted with Fallen Stars, while the latter can be crafted from Worm Teeth found as drops in The Corruption. Because they are piercing weapons, both arrow types can hit the Eye multiple times. However, one can also use Flaming Arrows, because the Eye of Cthulhu is weak to fire arrows, and takes more damage from them than it does from Jester's Arrows.

Throwing Knives act similarly to Shuriken, but they only hit twice. Even so, their comparable throwing rate and higher damage makes them a good compromise between Shuriken and bows. They can be found in Chests or bought from the Merchant during Blood Moons. If the player is willing to run through the surface of the corruption, they can obtain Vile Mushrooms, to produce Vile Powder, combining the powder with the throwing knives for Poisoned Knives. In the first form, the Eye has a respectable 12 defense, which negates 6 damage from all attacks. This can mean whilst Shuriken are hitting for 4 on average, Poisoned Knives will deal an average of 7. Combined with their damage-over-time poison effect, this makes them more than twice as effective.

The Musket also works, but you need many rounds, about 200. But, if you obtained a Minishark, it is a very effective weapon, as it can kill the eye in about a minute, with at least 400 rounds.

Grenades cause high damage and hurt everything in their blast, but may pose as much damage to the player as they do to the boss. Since the Eye will be spawning Servants or charging at the player most of the time, it's difficult to keep a safe distance from the explosion. If desired, Grenades can be purchased from the Demolitionist. A good strategy for Grenades is to lay them like a quick trap. As the Eye charges at you, you can predict its movements. Throw a grenade underneath you and run away as the Eye begins to charge. If timed correctly, the grenade will explode on contact with the Eye and you will be unharmed.

Molotov Cocktails avoid the danger of self-injury and work very well, especially in the second stage when Eye of Cthulhu will charge at you through the flaming puddles the Molotovs leave behind.

Because the boss typically flies out of reach, melee weapons are of limited use. However, the Starfury could fare well, as the stars falling from swinging it could deal high damage to the Eye. Even so, no matter what the weapon of choice, weapons with higher damage per second are preferred. The greater your damage, the shorter the fight and the better your chances of survival.

The Sunfury is very effective, as you can simply keep it on the floor while the EoC is underground, as it will end up hitting the EoC multiple times, and can set it on fire. However, you'll have to have gone to The Underworld first.

In Expert Mode Spiky Balls are very helpful in its second phase if you scatter them all over the floor of your arena

Potions
Finally, bring a batch of Lesser Healing Potions at the very least, in case you start taking too much damage. (Regular Healing Potions can be used if one has access to a Glowing Mushroom farm.) Three other helpful potions are the Regeneration Potion, the Ironskin Potion, and the Thorns Potion. Swiftness Potion, Hunter Potion, Archery Potion and Bowl of Soup/Cooked Marshmallow/Pumpkin Pie/Cooked Fish wouldn't hurt as well. They are easy to brew and last a few minutes each, so you will probably only need a couple.

First Phase
During this phase the Eye will spend most of its time floating above you. It will summon Servants of Cthulhu which fly towards you to attack, much like Demon Eyes, but will fly through walls and the ground. The Eye will still hurt you, if you run into it, so do not disregard it while you kill the Servants. If you start to get swarmed by too many Servants, temporarily switch to a fast swinging weapon such as a broadsword to get rid of them quickly.

A good strategy in this phase is to aim ranged weapons at the pupil of the Eye, since that is where it spawns the Servants. That way, you can kill the servants and damage the Eye. If you stand directly below the Eye and aim straight up with a piercing weapon, after a few seconds your projectile will fall back down and hit the Eye again. After spawning 3 or 4 Servants, the Eye will charge at you, attempting to ram you 3 times before hovering once more, so be prepared to evade. It turns rather slowly and roars as it charges, giving you time to prepare your next dodge. It can be helpful to begin to evade after the 3rd servant is spawned, as this will often allow you to dodge his first charge.

Rinse and repeat and the first phase should go down easily.

Eye of Cthulhu has 12 defense during this form, which negates 6 damage from every attack. As such, higher damage, lower speed weapons are more effective during the first form, such as the Musket or a Bow.

The expert variant of the Eye is considerably more challenging. The first phase of the fight is largely unchanged; however, the Eye's damage output is increased, making the margin for error much smaller even for well equipped pre-hardmode players. Ranged weapons are an asset to this fight, since the rate at which the Eye summons servants is increased, and heart drops are scarce. It is also recommended that the player expands the width of the arena to maximize evasion.

Second Phase
For the last half of the fight, the boss sheds its iris to reveal a fanged mouth. Make sure to take advantage of its transformation sequence as much as possible, since it just spins in place for a few moments and you can still damage it. It moves slightly faster and deals more damage when it hits you but it also has less defense. It will not be summoning any more servants, so this time it will simply keep rushing at you. When it does so, do not try to attack it- concentrate on dodging. It'll charge you 3 times, and then pause for a few seconds during which you can attack freely. Try to hit it with your strongest weapon. For newer characters who haven't made it to the Gold-Platinum/Silver-Tungsten stage, Shurikens are still your best bet.

In expert mode, the Eye of Cthulu becomes more spastic the lower its health gets. This is where a larger arena will benefit the player, as the sequence in which the Eye charges is different. At first, it will perform its regular 3 charges. After enough of its health has been depleted, it will perform a brief series of extremely quick dashes, usually at a steeper angle. As the battle progresses, the Eye will use this ability more freely, until its only action is to dart haphazardly back and forth, making contact with any weapon very rigorous.

For this phase, Hermes Boots is an asset. With a wide enough arena, running in a straight line while the Eye of Cthulu does his quick charge is fast enough to avoid any damage. Later in the fight, the player can use the Grappling Hook in tandem with the Hermes Boots for a quick escape, should he or she become stun-locked. As it is difficult to hit the Eye for the final percentage of his health, Spiky Balls are to be considered in this fight, provided the player has encountered the Goblin Army. Throwing Spiky Balls around the battlefield assures the player a number of hits on the Eye, even as it charges rapidly. Grenades are a useful alternative.

Survival
Like the Eater of Worlds, the Eye of Cthulhu will flee if the player dies during the fight. It will also flee if the player fails to defeat it before early dawn (exactly 4:30am, which you can determine with a Grandfather Clock or watch). The best way to avoid this is, like the other methods described above, a matter of preparation. Start the fight early after sunset (7:30pm), take lots of potions with you, and wear the best gear available to you. Normally however, the eye can be killed with shurikens in a little less than half the night, so while it is important to start the fight early, it is not essential to start the fight the moment that night begins.

Redux
As you upgrade equipment, the Eye of Cthulhu becomes easier and easier to defeat and is a great source of money. Craft stacks of Suspicious Looking Eye and immediately re-summon the Eye after defeating the previous one (keeping in mind that dawn is at 4:30 am). If you manage to dodge it during his charging attack, and he goes underground momentarily, hit it with fire arrows before he disappears in order to set it alight, and you can see the On Fire! debuff animation, making it visible. Keep in mind also that as of 1.3, bosses have minimap icons to increase their visibility. If you have a spear or vilethorn, try to hit it while he attempts to hover above you again.