Guide:Eye of Cthulhu strategies

The Eye of Cthulhu is one of the first bosses a player will encounter. The following are some hints, tips, and strategies to help defeat it.

Spawn Condition
Eye of Cthulhu can be spawned by fulfilling one of these conditions:
 * Have at least (200) Health, 10 Defense and at least 3 : it will then have a 33% chance of spawning at the start of the night. Note that this only works when it has yet to be defeated;
 * Use during night.

It must then be defeated before the day arrives.

First Phase
During this phase the Eye will spend most of its time floating above you. It will summon 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 to get rid of them quickly.

A good strategy in this phase is to aim mid-range 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 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 its first charge.

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 it on fire, making it visible. Keep in mind that in versions, bosses have minimap icons to increase their visibility.

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.

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 no 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.

For this phase, Hermes Boots is an asset. With a wide enough arena, running in a straight line while the Eye of Cthulhu 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 they 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. are a useful but riskier alternative, due to its collateral damage if it explodes too near to you.

Expert Mode
In the first phase of the fight it is more aggressive, acting very similarly to first phase Retinazer: it spawns servants while floating above the player, and will occasionally make a few lunges. It also enters the second phase at 65% health instead of 50%, spawning a lot of servants in that process. A piercing weapon is recommended for eliminating the servants.

In this part of the fight, after the 3 normal charges it will perform a brief series of extremely quick dashes at a steeper angle. As its health goes down, the Eye will use this ability more frequently, until its only action is to dart haphazardly back and forth, making it rather hard to hit. To avoid the charges, Hermes Boots should be used at the bare minimum.

Terrain preparation
An arena for the Eye of Cthulhu should be large enough to dodge and maneuver around in. The recommended size is just about the size of the screen, as the boss does not require a lot of mobility.

The simplest arena design consists of multiple rows of wooden platforms to have more room to jump and dodge. As the fight will be at night, add torches to improve visibility.

Another design is a long, completely flat surface. This allows you to dodge the Eye by running to the left or the right with Swiftness Potions or Hermes Boots.

Armor
The best armor to have at this point would be Gold or Platinum armor, although it can be difficult to obtain. Consider using these sets if you are having trouble beating the boss with weaker armors.

A full set of Silver armor or Tungsten armor is the easiest to get at this point, and it is a good choice for this fight. While it may seem tempting to use pieces of stronger armor (Gold, Platinum), doing so is unwise, as the Silver armor or Tungsten armor's set bonus provides more defense than mismatched armor. On the, the Boots of Ostara can be paired with Silver armor to complete the set bonus while increasing jump abilities, although using it with Tungsten armor will not grant the set bonus.

In versions, if you have taken out King Slime previously, the Ninja armor will be especially useful. While it provides less defense than Silver or Tungsten, it enhances the combat potential of throwing items, which are extremely effective against the boss.

The weaker Iron or Lead armor sets can be used, but caution must be taken, especially in the second phase, and should only be used if you are a good dodger.

If using magic weapons, you can use the Wizard set, which provides big buffs to magic weapon's stats.

Weapons
In general, long-range piercing weapons are recommended, as they are able to take out Servants and hit the boss.

Melee's options are fairly limited at this point, and mostly serve as a way to take out the low-hp Servants of Cthulhu. Certain melee weapons are able to launch projectiles, but may be difficult to come across.
 * For Melee Users:


 * Swords aren't very helpful against the boss itself, but can make short work of the Servants of Cthulhu without the need to aim. You should aim for a or a  at this point, but if you've been lucky and found enough  or, you can craft a  or a , which will perform even better.


 * Using projectile-launching broadswords instead of regular broadswords is highly recommended, as their sword slash can take out nearby servants and their projectile can hit the boss itself. Their only downside is that they can be rather difficult to come across compared to regular broadswords. The three projectile swords available at this point are the found rarely throughout the world or in Enchanted Sword Shrines, the  found in Ice Chests in the Ice biome, and the  found on Floating Islands.
 * Spears can be helpful, hitting both the boss itself and the servants with the same hit. The only spears available at this point are lacking in range, so consider using a more ranged weapon when the boss is in motion. The recommended spear at this point is, or the  found in Water Chests should suffice.
 * Enchanted Boomerang.png Boomerangs can be of great use due to their long range, but missing with a boomerang can leave the player open for a moment. An or  would be preferred. A  is not recommended, due to low damage.
 * are another type of melee weapon, and excel against the boss. A is the best choice at the moment.


 * For Ranged users:
 * Bows are some of the best weapons available at the moment. The best one is either the or .  deal the most damage to the boss itself and inflict Frostburn, but  can kill the Servants and hurt the Eye in the same shot.
 * The is another fast firing weapon to use, doing decently against both phases.


 * For Magic users:

Magic weapons are mainly good for beating on the boss itself, but can also be used to attack servants in a pinch. All magic weapons at this point are able to pierce through multiple enemies. More adventurous players can get their hands on much better weapons, and these should certainly be used for later "repeat engagements":


 * are the usual Magic weapon of choice at this point, with their long ranged piercing shots being a perfect fit for the boss battle. You should try for the Diamond or Ruby staves, with Emerald or Sapphire as second-best. The Amethyst and Topaz staves are short on damage for this fight.
 * , found on shelves in the Dungeon, can rarely be found in the upper areas that you can reach before fighting Skeletron. If you're lucky enough to get one, it can replace the Gem staves entirely.  It will help to put solid-block walls around your arena, so you can make use of the Water Bolt's ricocheting projectiles.
 * Those players who have delved into their "evil biome" may be able to get hold of the powerful magic weapons found in Shadow Orbs, Crimson Hearts, or the crates fished up in these biomes. The lacks some range, but the lingering thorn can hit the boss and servants many times, and can even pass through walls to hit it.  The  is similarly useful, as clouds can be set up to clear out the servants while also dealing steady damage to the boss.
 * Those who have not only broken orbs/hearts, but gathered Meteorite ore from the resulting crash sites, can use the, with its fast velocity and piercing properties. It does use a lot of mana (and you might not even have maximum mana)... unless you pair it with Meteor armor, which makes it free.  Both weapon and armor are crafted with.

A Summoner's options are extremely limited at this point of the game. Because there are only three summoner-class weapons available pre-hardmode, summoners have a very tight selection available, made worse because all of these weapons are extremely difficult to obtain at the point you have to fight the Eye. For first-time or unskilled players, it's better to completely avoid focusing on the Summoner class until later in the game. For those who still want to try, get ready for a much harder challenge.
 * For Summoners:


 * Slime_Staff.png Baby_Slime_(minion)_(animated).gif Out of the three weapons available, the Slime Staff is the only that does not require you to fight a much stronger boss, or travel to a very dangerous place. Unfortunately, it is locked behind a 0.01% / drop chance for all Slimes and Slimed Zombies with the minor exceptions of Pinky and the Sand Slime. Even if you somehow managed to get it, you haven't obtained a fantastic weapon for such a painstaking grind session (or stroke of luck). The Baby Slime deals very little damage and cannot fly. Even if it manages to attack the Eye, its piercing attacks will activate invincibility frames for the boss, preventing you from damaging it. It's best to skip this weapon altogether.
 * Imp_Staff.png Flying_Imp.gif The Imp Staff is the most powerful summoner weapon available pre-Hardmode, as the flying imps deal 21 damage and inflict the On Fire! debuff against enemies, at the cost of being completely ineffective underwater - a flaw that does not come into play when fighting the Eye of Cthulhu. To get this weapon, you need to craft it on an anvil with 17 Hellstone Bars, the most powerful ore before hardmode only found in The Underworld, the last location you visit before fighting the Wall of Flesh and activating hardmode. Ironically, out of all the three summoner weapons, this is the easiest to acquire – but is by no means truly easy. Assuming you can fish up a Reaver Shark, it is only a matter of playing with water and lava to produce and mine Obsidian, and carefully mining Hellstone. Caution is necessary, as the enemies in the Underworld are very dangerous and can easily kill you. For more information, see Guide:Mining_techniques.

Thrown weapons are at their best at this stage of the game, with a wide selection of effective weapons to use against this boss. Most of them are also cheap or easy to obtain, allowing the player to rack up stacks of thrown weapons.
 * For Throwing Users:


 * 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.
 * or perform similarly to Shurikens but do a lot more damage.
 * cause high damage and hurt everything in their blast, but may pose as much danger 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 . 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.
 * are useful and deal good piercing damage, which makes them an amazing choice on the first phase.
 * 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.
 * are very helpful in its second phase if you scatter them all over the floor of your arena.

Accessories

 * A or equivalents can aid in avoiding the rams, although this is less necessary with a good arena.
 * A Grappling Hook is also very useful if you can grapple onto platforms above you quickly.
 * or equivalents help by making it easier a chance to dodge the second phase's rams. In Expert Mode, these are almost required, as the Eye of Cthulhu will perform rapid dashing attacks.
 * The will give a significant damage boost to most weapons available at the moment.
 * If you find one, a can help speed up life regeneration, making lasting a longer fight easier. A  should also be used for Magic players, as it regenerates Mana faster.

Any accessory with the Warding modifier will be useful if you come across one, and the extra four defense can be used to make up for lower-tier armor, like Iron or Lead.

Potions

 * The most helpful potions are the, the , the , and the.
 * Any food item that gives the buff is welcomed, especially so for expert mode.
 * significantly increases the damage output of bows.
 * and are good for magic users.

Slimy Saddle Strategy
An excellent strategy to beat the Eye is to use the Slimy Saddle and bounce on the eye while at the same time attacking it with a ranged weapon. The eye will move toward you and you will bounce on top of it continuously dealing damage. If you want to try this strategy, make sure you have some forms of preventing fall damage (i.e,) the Lucky Horseshoe, Grappling Hook, an Umbrella, or Cloud in a Bottle.

Magic Mirror Strategy
During the Second Phase, if you have your spawn point nearby, you can run one way and attack, and just when you think that the Eye is going to charge, use a Magic Mirror or Recall Potion to teleport to spawn, now running the other way, evading the attack and being left to open fire.

Railway Strategy
Another great strategy is to build a long railway at least 400 blocks long, with each end hammered into a bumper. When the Eye spawns, start moving and continue to move whilst shooting at it. It may take longer than other methods, but it requires little mobility and you take minimal damage. Also, this strategy works better if in single player or all players in a multiplayer world are together in the same area.

Another Railway Strategy
One strategy is to make a railroad track that is going around the boss and attack him with a ranged weapon and having a endless musket ball pouch or quiver can help.

fr:Guide:Stratégies de l'Œil de Cthulhu