Guide:Eye of Cthulhu strategies

Type	Boss
Environment	Surface + Night Space + Night
AI Type	Duke Fishron AI
Damage	2336; 40 when below 145 health54; 60 when below 185 health
Max Life	1400/28002366/36403016/4641
Defense	0
KB Resist	100%
Immune to
Coins	3750
Charge
Chain charge

Type	Boss
Environment	Surface + Night Space + Night
AI Type	Eye of Cthulhu AI
Damage	15/30/45
Max Life	2800/3640/4641
Defense	12
KB Resist	100%
Immune to
Coins	3750
Hurt
Killed

Template:Grp status

This is a Guide page.
This means the page will walk you through a specific task, strategy, or enemy/boss fight.

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 NPCs: 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 Suspicious Looking Eye during night.

It must then be defeated before the day arrives.

The Fight

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 Sword 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 PC, Console, Mobile, Old Chinese, tModLoader, and tModLoader Legacy 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 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 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.

General Strategies

General Tips

This content is transcluded from Guide:Practical Tips § Combat.

For nocturnal bosses, starting the battle just after the sun sets (7:30 PM) will provide the maximum amount of time to defeat the boss. In Hardmode, the Moon Charm and/or Moon Stone and their upgrades are also useful at night.
Boss battles can be won or lost before the battle ever starts. Choose your equipment and have it ready; find and/or make potions and placed buffs; use the highest-tier food you have available; set up an arena appropriate to the boss; learn the strategies for the boss you're facing.
Prepare your Boss-fighting arena with adequate lighting, Campfires and Heart Lanterns for health regeneration, and Stars in Bottles for mana regeneration if you use magic. Bast Statues will provide a significant defensive boost. Garden Gnomes and (if underground) proper torch placement will reduce damage taken and increase damage dealt due to the luck. Note Torch God's Favor helps with this. Honey pools can also be used for extra health regeneration.
Sunflowers provide the Happy! buff to players within a 50-tile radius, which grants a +10% movement speed bonus and 17% reduction in enemy spawn rate.
Always carry around a stack of the highest-tier healing potion available, as relying only on natural Health Regeneration is not a good idea. Depending on the game stage, this can include items such as Mushrooms or Honeyfins. On the PC, Console, Mobile, and tModLoader versions, Restoration Potions are healing potions with a shorter cooldown.
- Likewise carry mana potions, if you use Magic.
- The Strange Brew is also an option, but its weak healing effect will trigger the Potion Sickness cooldown as well as Mana Sickness. On the Old-gen console version, Windows Phone version, Old Chinese version, Nintendo 3DS version, and tModLoader 1.3-Legacy version, Restoration Potions can save a slot, but will likewise trigger both cooldowns.
It is suggested to build houses for the Dryad and the Nurse NPCs in your arena. The former casts the Dryad's Blessing buff, which increases your defense and provides you with a thorns-like effect, while the latter can heal and remove debuffs instantly, at the cost of some coins.
Bosses are displayed on the Minimap: Follow the boss's icon to track it when you're struggling to find it. You can identify the boss icons by checking their respective wiki pages.
Once you have freed the Mechanic in the Dungeon, you can use Wire to enhance your arena with Traps and helpful Heart and Star Statues. The former helps to damage the enemies, though be careful to set them up correctly in order not to hurt yourself during the battle. The latter will spawn heart and star pickups, respectively. Connect these devices to timers.
It may be useful to summon and kill the Eye of Cthulhu or King Slime before summoning any harder boss in order to spawn an extra one-use pool of Hearts. Note that this will prevent any Heart Statues from spawning new Hearts.
Remember to use the Sharpening Station, Ammo Box, Crystal Ball, Bewitching Table, and Slice of Cake before you go to explore or battle bosses/invasions. These will give boosts that are useful to take, with the first four being class-specific. They give Sharpened, Ammo Box, Clairvoyance, Bewitched, and Sugar Rush, respectively.

Terrain preparation

EoC arena — A basic arena made for the Eye of Cthulhu.

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.

Gearing up

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 and Tungsten armor's set bonus provides more defense than mismatched armor. On the Mobile version, 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 PC, Console, Mobile, Old Chinese, tModLoader, and tModLoader Legacy 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.

For Melee Users

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.

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 Gold Broadsword or a Platinum Broadsword at this point, but if you've been lucky and found enough Demonite or Crimtane Ore, you can craft a Light's Bane or a Blood Butcherer, 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 Enchanted Sword found rarely throughout the world or in Enchanted Sword Shrines, the Ice Blade found in Ice Chests in the Underground Snow, and the Starfury 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 The Rotted Fork , or the Trident found in Water Chests should suffice.
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 Enchanted or Ice Boomerang would be preferred.
Yoyos are another type of melee weapon, and excel against the boss. A Rally 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 Gold Bow or Platinum Bow. Frostburn arrows deal the most damage to the boss itself, but Jester's Arrow can kill the Servants and hurt the Eye in the same shot.
The Snowball Cannon 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.

Gem staves are the main Magic weapon of choice against the eye, with their long ranged piercing shots being a perfect fit for the boss battle. You should aim for a Ruby Staff, Emerald Staff, or Sapphire Staff at this point. The Amethyst Staff and Topaz Staff tend to be lacking in damage output. If you manage to get the materials for the Diamond Staff using it is a must.
Water Bolt, normally found on shelves of the Dungeon, can rarely be found in the accessible areas, making it possible to obtain before beating Skeletron. If you're lucky enough for this to happen, using it in place of Gem staves would be a good idea. If you re-adjust your arena to contain solid-block walls surrounding it, you can make use of the Water Bolt's ricocheting projectiles.
Vilethorn can be of great use to more ambitious players. While it's somewhat lacking in range, the lingering thorn can hit the boss and servants many times, and can even pass through walls to hit it, if you lack a platform arena. It's found in Corruption-only Shadow Orbs, so you need to be cautious when obtaining it.
Crimson Rod is similarly useful. Clouds can be defensively set up to avoid having to deal with the servants, while also dealing steady damage to the boss. It's found in Crimson-only Crimson Hearts, so be careful while trying to obtain it.
Space Gun, with its fast velocity and piercing properties makes it ideal for defeating the boss. However it heavily consumes mana, especially at a point in the game where the player might not have maximum mana, but in combination with the Meteor armor's set bonus of removing the mana cost of the Space Gun, it can be one of the easiest ways to take down the boss. It is crafted with Meteorite Bars.

For Summoners

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.

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% / 0.014% 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.
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#Mining_Hellstone.

For Throwing Users

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.

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.
Throwing Knives or Poisoned Knives perform similarly to shurikens but do a lot more damage.
Grenades 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 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.
Javelins are useful and deal good piercing damage, which makes them an amazing choice on the first phase.
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.
Spiky Balls are very helpful in its second phase if you scatter them all over the floor of your arena.

Accessories

A Cloud in a Bottle 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.
Hermes Boots 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 Shark Tooth Necklace will give a significant damage boost to most weapons available at the moment.
If you find one, a Band of Regeneration can help speed up life regen, making lasting a longer fight easier.

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 Regeneration Potion, the Ironskin Potion, and the Swiftness Potion.
Any food item that gives the Well Fed buff is welcomed.
Archery Potion significantly increases the damage output of bows.
Magic Power Potion and Mana Regeneration Potion are incredibly good for magic users.

Other Tips

This content is transcluded from Eye of Cthulhu § Tips.

The Eye of Cthulhu drops either Demonite or Crimtane Ore. While the corresponding set of armor and a number of tools additionally require Shadow Scales or Tissue Samples respectively—which the Eye does not drop—the sword, bow, axe, yoyo, and fishing pole can be crafted with only the bars.
Due to the ease of crafting its summoning item and relatively low difficulty, farming the Eye of Cthulhu is one of the more effective ways of making money prior to Hardmode. It drops 3 / 750 up front, plus ores which can be sold as bars for twice (Demonite) or triple (Crimtane) that amount.
The Eye of Cthulhu will only spawn randomly if a player has more than 10 defense. Taking defense-boosting equipment off before dusk can prevent it from spawning randomly.
The boss looks at the player it will follow, which can be helpful information in multiplayer.
In classic mode, it is most vulnerable during its transformation, because it neither moves nor attacks, but there is only a brief window of opportunity for this. In Expert Mode or above, it sheds a plethora of minions upon transformation, which protects it while it transforms.
Because there are no location-based requirements for summoning, defeating multiple Eyes of Cthulhu in an area can be an effective setup for harder boss fights as the dropped Hearts can be picked up mid-fight as needed, though killing an Eye of Cthulhu for that purpose must be balanced with the time it takes away from killing a night-only boss.
While it may seem that killing it on a Corruption-generated world would yield more money than doing so in a Crimson-generated world, as it will drop additional Unholy Arrows, Crimtane Ore and Bars sell for a 30% higher price than their Demonite counterparts, making them much more profitable.
In singleplayer, the player can repeatedly pause the game using Autopause in order to properly aim at the Eye of Cthulhu during its dash attacks.

Specific Strategies

Slimy Saddle Strategy

An amazing 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 Lucky Horseshoe, Grappling Hook, 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.

↑ ^1.0 ^1.1 Information taken from the PC 1.4.2.3 source code, method AI() in Terraria.NPC.cs under aiStyle == 4 There may be inaccuracies, as the current PC version is 1.4.4.9.
↑ ^2.0 ^2.1 ^2.2 ^2.3 Information taken from the PC 1.4.0.5 source code, RegisterBoss_EOC() in Terraria.GameContent.ItemDropRules.ItemDropDatabase.cs. There may be inaccuracies, as the current PC version is 1.4.4.9.
↑ Information taken from the PC 1.4.0.5 source code, DoDeathEvents_DropBossPotionsAndHearts() in Terraria.NPC.cs. There may be inaccuracies, as the current PC version is 1.4.4.9.

[eocai-1] 1.0 ^1.1 Information taken from the PC 1.4.2.3 source code, method AI() in Terraria.NPC.cs under aiStyle == 4 There may be inaccuracies, as the current PC version is 1.4.4.9.

[drops-2] 2.0 ^2.1 ^2.2 ^2.3 Information taken from the PC 1.4.0.5 source code, RegisterBoss_EOC() in Terraria.GameContent.ItemDropRules.ItemDropDatabase.cs. There may be inaccuracies, as the current PC version is 1.4.4.9.

[badger-3] Information taken from the PC 1.4.0.5 source code, DoDeathEvents_DropBossPotionsAndHearts() in Terraria.NPC.cs. There may be inaccuracies, as the current PC version is 1.4.4.9.

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