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Terraria Wiki
This is a Guide page.
This is a Guide page.
This means the page will walk you through a specific task, strategy, or enemy/boss fight.
Status: Subject to revision (This Guide does not meet certain quality standards and may be heavily outdated.)
  • Issues:
     • Most likely outdated since 1.4. Remember not to delete pre-1.4 content; use {{eicons}} and {{eversions}}!
  • This guide is about Brain of Cthulhu, which is exclusive to Crimson worlds. Players playing in Corruption worlds should check Guide:Eater of Worlds strategies instead.

    Brain of Cthulhu Trophy.png "A horrible chill goes down your spine..." Brain of Cthulhu Trophy.png

    The Brain of Cthulhu is a Pre-Hardmode boss. It is The Crimson counterpart of Eater of Worlds.

    Brain of CthulhuFirst Form
    Brain of Cthulhu (First Phase).gif
    Map Icon Brain of Cthulhu.png
    Map Icon
    Classic mode icon.png Classic
    Expert mode icon.png Expert
    Master mode icon.png Master
    AI TypeBrain of Cthulhu AI
    Max Life1000/1700/2167
    300051006487 (with creepers) [1]
    KB Resist50%/55%/60%
    Immune toConfused
    Brain of CthulhuSecond Form
    Brain of Cthulhu (Second Phase).gif
    Map Icon Brain of Cthulhu.png
    Map Icon
    Classic mode icon.png Classic
    Expert mode icon.png Expert
    Master mode icon.png Master
    AI TypeBrain of Cthulhu AI
    Max Life1000/1700/2167
    KB Resist50%/55%/60%
    Immune toConfused

    Spawn Conditions[]

    The Brain of Cthulhu can be spawned by fulfilling one of these conditions:

    It must then be defeated within the Crimson: getting out of it will make it retreat and despawn.

    The Fight[]

    Brain of Cthulhu has 2 phases, with the latter starting after all CreeperCreepers have been dealt with.

    First Phase[]

    The Brain cannot be attacked in this phase, only the Creepers can. The Brain will teleport to a spot in the arena, then slowly advance towards you. The Creepers will follow shortly after and will clump up with the brain for a few seconds before the Brain teleports again and the Creepers will follow. The idea is that the Brain will teleport behind you, which will make the Creepers fly into you, causing damage. Jump out of the way, either by using your platforms or with an extra jump, then attack the Creepers. Use piercing weapons to speed up the process. When a Creeper dies it can drop either Crimtane OreCrimtane Ore or Tissue SampleTissue Sample.

    Second Phase[]

    When all of the Creepers are dead, the Brain will split, revealing a Heart with an Eye on the inside. The Brain teleports much more frequently, often at unexpected angles, and will try to ram into you. The Brain only has 1000 / 1700 / 2167 health, so it can be killed fairly quickly. Keep using your platforms to jump out of the way. Use your strongest weapon to take down the Brain. If you have a weapon with high knockback, it will excel at dealing with the Brain, so much so that it's possible to stand in one location and attack it whenever it gets close.

    Expert Mode[]

    The Creepers are much more aggressive. They will actively try to fly into you, even ignoring the Brain if it means an opportunity to land an extra hit or two. They can also inflict a large variety of debuffs:

    • ConfusedConfused: reverses the movement buttons;
    • PoisonedPoisoned: saps 2 health per second;
    • BleedingBleeding: stops health regeneration;
    • DarknessDarkness: reduces vision;
    • SilencedSilenced: makes you unable to cast any Magic weapons;
    • Broken ArmorBroken Armor: reduces your Defense by half;
    • WeakWeak: reduces Melee damage and Attack Speed, Movement Speed, and Defense by 4.

    During the Second Phase, the Brain will spawn clones of itself around the player. They serve as decoys, and while they cannot be attacked they can confuse the player. They start off as barely visible but as the Brain loses more health the clones will become more opaque. At low health the clones will be completely visible. The Brain will also become faster as it loses health. Life-draining debuffs such as On Fire and Frostburn, or a Hunter Potion will help distinguish them. Additionally, summoned Minions will always target the correct copy. Unlike the Lunatic Cultist clones, the Brain of Cthulhu clones do not appear on the map, making it trivial to tell which direction the real boss is coming from.

    General Strategies[]

    General Tips[]

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

    • 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, CampfireCampfires and Heart LanternHeart Lanterns for health regeneration, and Star in a BottleStars in Bottles for mana regeneration if you use magic. Bast StatueBast Statues will provide a significant defensive boost. Garden GnomeGarden 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. HoneyHoney pools can also be used for extra health regeneration.
    • SunflowerSunflowers 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. As of, Restoration Potions are healing potions with a shorter cooldown.
      • Likewise carry mana potions, if you use Magic.
      • The Strange BrewStrange Brew is also an option, but its weak healing effect *will* trigger the Potion Sickness cooldown as well as Mana Sickness. Before, Restoration potions can save a slot, but will likewise trigger both cooldowns.
    • 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 MechanicMechanic in the Dungeon, you can use WireWire to enhance your arena with Dart TrapTraps and helpful Heart StatueHeart and Star StatueStar 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 3 Second Timertimers.
    • 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 StationSharpening Station, Ammo BoxAmmo Box, Crystal BallCrystal Ball, Bewitching TableBewitching Table, and Slice of CakeSlice 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 SharpenedSharpened, Ammo Box (buff)Ammo Box, ClairvoyanceClairvoyance, BewitchedBewitched, and Sugar RushSugar Rush, respectively.

    Terrain Preparation[]

    Standard 5 layer arena.

    Your arena will have to be built in The Crimson, because it can only be summoned there. Since the Brain of Cthulhu spawns as soon as you smash a third Crimson Heart, you're likely to be in a very enclosed area when the fight begins. This can lead to you being swarmed by the Creepers and getting overwhelmed. This can be avoided by preparing the chasm's main chamber as an arena beforehand, and choosing which Hearts to break first:

    • For the first two, pick the least convenient hearts (distant, above the main chamber, underwater, etc).
    • For the third, pick the closest to the main chamber, toss a Bomb or another explosive, and quickly go to your arena while it falls.

    If you have access to the Dryad, purchase several stacks of Purification Powder and completely convert the main chamber so that there is no Crimstone Block exposed to air, which prevents you from needing to deal with other Crimson-based enemies during the fight, although standard Underground enemies may spawn in their place. Set up several rows of platforms all the way across the central chamber, close enough that you can jump up to the next platform, and light up everything.

    If summoned with a Bloody Spine, then the arena can simply be made in the Surface, however, do not make it very tall, as jumping too far above it will be considered exiting the Crimson, causing the Brain of Cthulhu to despawn. If you have already prepared the central chamber as an arena for a prior fight, use the Bloody Spine there to avoid a despawn.

    The Brain Of Cthulhu is unique in the way it reacts when you die. Unlike every other boss, The Brain Of Cthulhu does not despawn upon your death, rather it keeps ramming into the spot you died. You can use this to your advantage by using Purification Powder to clear out a small area to make a basic house. Then if you place a bed inside, you have a respawn point in the main chamber. Now, there is virtually no consequence to dying in the fight, as you can keep respawning and continue the battle. Note: as of 1.4 this no longer occurs.

    Gearing up[]

    It is recommended to have at least 200 Life and 100 Mana, which requires 5 Life CrystalLife and Mana CrystalMana Crystals: if you've done some spelunking you're bound to have come across this many.

    Gold HelmetGold or Platinum HelmetPlatinum armor is recommended if you are willing to mine enough of their respective ores. You can get Crimson HelmetCrimson armor by killing enough Creepers without necessarily defeating the Brain itself. Silver HelmetSilver or Tungsten HelmetTungsten armor are slightly riskier, but ultimately also viable options, especially if you are confident in your dodging abilities.

    It is possible to kill the Brain of Cthulhu with just Iron HelmetIron armor or Lead HelmetLead armor, but the fight will be a bit more dangerous. Pumpkin HelmetPumpkin armor is another viable option, rewarding slightly less defense than Iron / Lead, but increasing your damage output, which can ensure the fight is completed quickly.

    The Wizard HatWizard Set is the best offensive mage set available but has little defense. The Jungle HatJungle armor gives higher defense but has weaker magic offensive stats.

    The Flinx Fur CoatFlinx Fur Coat is the only armor that can boost summon damage at this stage of the game.

    Rocket BootsRocket Boots or its upgrades are recommended as they can help with dodging.

    Accessories with Menacing or Warding modifiers will be most efficient here if you have them, but are not required.

    On the Nintendo 3DSNintendo 3DS version version, BoneBones drop from Skeletons, so Necro HelmetNecro armor can be used here.


    For Melee users:

    • Blood Butcherer Any large sword, such as the Blood Butcherer, will prove effective against the Creepers.
      • The Falcon BladeFalcon Blade is useful for the Brain of Cthulhu's second phase, as its rapid speed, somewhat high damage, and decent knockback will keep it at bay.
      • The KatanaKatana, which is sold from the Traveling MerchantTraveling Merchant, is a fast sword with decent knockback and a high critical rate.
    • The Rotted Fork A spear is a great weapon against the Brain of Cthulhu, especially during the second stage. Suggested options are the TridentTrident and The Rotted Fork.
    • The Meatball A flail of some kind is beneficial for taking out the Creepers; the easiest to obtain would be the Flaming MaceFlaming Mace (craftable from a MaceMace, which can be found in Gold ChestGold Chests located underground). Even more effective would be The Meatball, which would require killing a few Creepers (but not necessarily the Brain itself). You could instead try to obtain the Chain KnifeChain Knife, rarely dropped by Cave BatCave Bats, but unlike the previously mentioned flail, it cannot pierce.
    • Artery A yoyo would be useful against the Brain in its second stage; the Artery is a great choice at this point, although the Code 1Code 1 (available from the Traveling Merchant) is also a good option if you can get one, having higher damage but quite low knockback.

    For Ranged users:

    • Tendon BowTendon Bow is the most powerful bow at this stage. You can combine it with Jester's ArrowJester's Arrows, which greatly help to kill the swarm of Creepers. However, you can also use Frostburn ArrowFrostburn Arrows as a slightly cheaper alternative; the FrostburnFrostburn debuff will be helpful during the second stage. Also, you can use Flaming ArrowFlaming Arrows as a fallback, with their On Fire!On Fire! debuff also helping during the second stage.
    • Blood Rain BowBlood Rain Bow does 5 less damage than the Tendon Bow but fires several streams at once. Its inaccuracy is offset by the many creepers to hit in the first stage and the large size of the Brain in the second stage. If you use this underground, make sure you're in a large enough space that the blood can fall freely from the top of the screen.
    • Molotov CocktailMolotov Cocktails, while expensive to make (as PinkyPinkies aren't common), is a superb weapon. The splash damage and the fire that hits multiple times can keep the Brain away in its second stage.
    • If you are willing to risk, GrenadeGrenades are great choices for dealing with the Creepers, but you have to watch out for the blast radius, as you will take damage from it.
    • Non-explosive consumables, such as ShurikenShuriken and Throwing KnifeThrowing Knives, can be effective since they penetrate multiple enemies, meaning that they can hit multiple Creepers.
    • Spiky BallSpiky Balls with their Penetration are very helpful for killing Creepers. Since they take a while to disappear, it's a good idea to throw many of them into your arena before starting the fight.
    • As The UndertakerThe Undertaker can be obtained very easily (as it's a guaranteed first-time loot from the Hearts), it's a good weapon to use against the Brain. The Musket BallMusket Balls that spawn with it should be sufficient, but you can craft (or buy) Silver BulletSilver Bullets / Tungsten BulletTungsten Bullets, which deal slightly more damage. Alternatively, once you obtain The Undertaker, you can gain access to the Arms DealerArms Dealer, who can provide you with a MinisharkMinishark, which is effective against the Creepers and the brain in the second phase if used with Silver or Tungsten bullets due to its rate of fire, and it will probably knockback-lock it, making tons of damage.
    • Another gun that you might have acquired at this point is the BoomstickBoomstick. It may be useful in taking out the creepers, as they have low individual health and there are many of them.

    For Magic users:

    • The Crimson RodCrimson Rod is a great support weapon that can easily be obtained through Crimson Hearts.
    • A Ruby StaffRuby Staff (or, failing that, a Emerald StaffEmerald Staff) is easy to make, and with its decent damage and piercing ability, it is particularly effective against the Creepers. A Diamond StaffDiamond Staff or Amber StaffAmber Staff would work as well or better, but (being harder to obtain) are not worth going out of your way for.
    • If you're willing to make a quick detour to a Corruption world, the VilethornVilethorn works fantastically against the Creepers and is a great weapon in general.
    • If you already farmed a Meteorite crash site for Meteorite, you can use the excellent Space GunSpace Gun with Meteor HelmetMeteor armor: its piercing ability will clear out the Creepers fairly easily, and it will cost no mana thanks to the set bonus of Meteor armor. As of 1.4, meteorites now only spawn after the Brain of Cthulhu has been defeated. However, this is still a valid strategy if you have already defeated the Brain of Cthulhu at least once.
    • The Demon ScytheDemon Scythe is an excellent choice for dealing high damage to the second phase if you're willing to get it.

    For Summoners:



    • The Cloud in a BottleCloud in a Bottle will give you a double-jump ability which will greatly help with evasion. Look out for the alternative versions, some of which are more performant: the Fart in a JarFart in a Jar, the Tsunami in a BottleTsunami in a Bottle, the Blizzard in a BottleBlizzard in a Bottle, or the Sandstorm in a BottleSandstorm in a Bottle.
    • The Hermes BootsHermes Boots will increase your speed and aid greatly in evasion. You can upgrade them to the Spectre BootsSpectre Boots for the added bonus of a few seconds of flight, but this requires the Goblin TinkererGoblin Tinkerer, which you may not have yet. Even better is the Lightning BootsLightning Boots, however, they can take a while to obtain.
    • The Band of RegenerationBand of Regeneration is a decent accessory that will slowly regenerate your life; it equates to one heart restored every 40 seconds. Not terribly useful but it's suggested if you have a slot you need to fill.
    • The Anklet of the WindAnklet of the Wind gives a basic 10% speed boost, which will help out with evasion. You can replace it with the AgletAglet which is much easier to find but only offers a 5% speed boost.
    • The Frog LegFrog Leg will give you improved jumping abilities, including increased height and automatic jumping but it can only be found by fishing, though it is rather rare.
    • If one is playing in Expert Mode, the Shield of CthulhuShield of Cthulhu is a great choice for quick evasion, and extra damage in the Brain's second phase. Specifically, if you dash whenever it disappears and reappears, you will either safely avoid the brain or run directly into it; either way, you won't take damage.
    1. Information taken from the Desktop version Desktop source code, method AI() in Terraria.NPC.cs (under <nowiki>aiStyle == 54</nowiki>); also method GetBrainOfCthuluCreepersCount() in Terraria.NPC.cs There may be inaccuracies, as the current Desktop version Desktop version is