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Terraria Wiki
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.
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  • Retinazer Trophy.png "This is going to be a terrible night..." Spazmatism Trophy.png

    The Twins are the Hardmode version of the Eye of Cthulhu. They are part of the trio of the mechanical bosses, alongside with The Destroyer and Skeletron Prime.

    The TwinsHardmode exclusive
    The Twins.png
    Classic mode icon.png Classic
    Expert mode icon.png Expert
    Master mode icon.png Master
    Max Life430006450082237 (total)
    KB Resist100%
    Immune toPoisonedConfused

    Spawn Condition[]

    The Twins can be spawned by fulfilling any of these conditions:

    • Smash a Demon AltarDemon / Crimson AltarCrimson Altar. They will then have a 10% chance of appearing when night falls. Note that this condition is shared with the rest of the trio, which increases as more mechanical bosses are defeated, and thus it's not guaranteed if they have yet to be defeated, and will only work if The Twins have yet to be defeated;
    • Use a Mechanical EyeMechanical Eye during Hardmode at night.

    they must then be defeated before the night ends.

    The Fight[]

    The Twins, as the name suggests, are two separate monsters, both of which must be defeated. They have a combined health of 43,000 / 64,500, shared between them. Retinazer, distinguished by its red iris and that it fires lasers. Spazmatism, distinguished by its green iris and that it fires cursed flames.

    When reduced to 2/5 health, they will transform, gaining a slight boost in offense and defense. Each Eye transforms independently once reduced to 8,000 / 12,000 HP (Retinazer) / 9,200 / 13,800 HP (Spazmatism); the other eye remains in its original form until it is reduced to the appropriate amount. When one is destroyed, the other will continue attacking in the same pattern.

    It is a good idea to take them out one at a time, because if one dies first, it will be much easier to defeat the other one.


    In its first form, Retinazer will fire lasers at the player at a steady but somewhat slow rate. This is occasionally interrupted by charging attacks, which mirror that of its partner. Retinazer does slightly less damage than Spazmatism, but this is offset by its higher accuracy thanks to the speed of the lasers. When not charging, Retinazer will always be aligned diagonally with the player, positioned above them.

    When it changes into its second form, it will no longer engage in charge attacks. Instead, its lasers will progressively fire at a faster rate as it loses health. This is occasionally supplemented by a weaker but much more rapid laser attack that tracks extremely well. To avoid this, try to fall as fast as you can, and you can be left unscathed. With wings it is possible to "zig-zag" up and down to dodge the lasers. This is made trickier as the fight goes on, with Retinazer using more rapid and fast lasers that are much harder to dodge.


    Spazmatism, like Retinazer, varies between firing Cursed Flames from a distance and engaging in charging attacks. The flames do more damage than the lasers, but are not as fast and thus easier to dodge. However, the Cursed Inferno debuff can be very dangerous for its high damage over time and its ability to stop health regeneration. Its charge attacks are faster and more agressive than Retinazer.

    Spazmatism's second form changes his attack pattern dramatically compared to Retinazer. Its cursed flame attack becomes a constant stream of flame, which will last for several seconds (and deal large amounts of damage). However, it does not chase the player quite as quickly as it does in its first form, making avoiding the attack somewhat easier. Once it stops spewing flame, it will charge with greatly increased speed, which also does a lot more damage. Dodging these charges is quite difficult. Much like Retinazer, fall as fast as you can while he is charging, and you should be okay. Misdirecting Spazmatism's charges is easier than it sounds; if you jump as he slows down, he will charge over you. This causes Spazmatism to charge at you from either above or below, making him easier to dodge if you just run.

    Which to defeat first[]

    The following lists shows Pros and Cons by defeating one of the Twins. Players generally kill Spazmatism first.

    Defeating Retinazer first:

    Pros: Retinazer has a ranged attack, and defeating this Twin first will assist players who are bad at dodging, afraid of lasers, or have a relatively low movement speed.

    Cons: Retinazer has many, many lasers to dodge, and, in addition, if you are a slow player, defeating Retinazer can be the more difficult of the two Twins to fight.

    Defeating Spazmatism first:

    Pros: Damage from Cursed Inferno can easily add up, so if you defeat him first, you won't have to deal with that for as long. Keeping Retinazer in its first form can allow you to easily heal to full before killing it.

    Cons: Attempting to defeat it as either a slow or melee player (unless you have a melee weapon that shoots a projectile like the Beam Sword or the Ice Sickle) can make dodging the eye fire more difficult.

    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 CharmMoon Charm and/or Moon StoneMoon 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, 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.
    • It is suggested to build houses for the DryadDryad and the NurseNurse NPCs in your arena. The former casts the Dryad's BlessingDryad'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 Silver Coincoins.
    • 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[]

    The Sky above the surface is highly recommended for the Twins arena, as vertical movement is required to dodge most of the attacks.

    • A very long Sky Bridge (if possible made out of Asphalt BlockAsphalt or Frozen Slime BlockFrozen Slime Blocks) is optimal. Continuously running with Spectre BootsSpectre / Lightning BootsLightning / Frostspark BootsFrostspark / Terraspark BootsTerraspark Boots causes both to miss you with their projectiles very often, and keeps each Twin at a stationary horizontal position most of the time, allowing you to fire continuously at it without switching your aim. Wings will help dodge each of the Twins' second phases. Using Asphalt can negate the need for Boots, while using them can allow you to avoid taking damage completely. However, try not to run too fast if you use Boots and Asphalt, as Retinazer may fall behind and despawn. Spazmatism, however, is fast enough to keep up. Regular stone blocks can be used too if you have obtained the Blessed AppleBlessed Apple.
    • The standard Boss arena of several layers of Platforms may be of use, as it allows firing and maneuvering in any direction. A solid ceiling just above your top platform will block Retinazer's beam attacks, as Retinazer always flanks from above.
      • Also, a wall on both sides of a small area can block Spazmatism's cursed fire, but be careful not to run out of time from covering behind the wall. It is helpful to have a one block hole one block up to shoot through. This is more useful if you want to try tanking the boss with the above tip of heart statues. If you can tank the hits with the help of heart statues, you can gun down Retinazer while Spazmatism is only able to charge at you.
    • A safety box in the ground isn't bad either, if you acquired the Daedalus StormbowDaedalus Stormbow. That way you could attack Retinazer while its laser can't hurt you in the box. In order to attack Spazmatism make the box one block from the surface and bring Holy ArrowHoly Arrows, the impact from the stars could hurt it. Stay close to the edge so the Cursed flames can't hurt you.
    • You can also use Minecart TrackMinecart Track when building a sky arena to avoid the Twins attack while doing a ton of damage with ranged weapons.

    Gearing up[]

    If you already defeated at least one of the Mechanical Bosses, you can explore the Underground Jungle for 20 Life FruitLife Fruits. These will increase your maximum life to 500, which can help to defeat the rest of the Mechanical Bosses.


    • Adamantite armorAdamantite armorAdamantite armorAdamantite armor provides the greatest overall increase to all stats. Melee and ranged users should substitute in a Frost BreastplateFrost Breastplate to increase damage output and defense without sacrificing anything important.
    • Titanium armorTitanium armorTitanium armorTitanium armor is a great choice due to its also high stats and the Titanium BarrierTitanium Barrier / Shadow DodgeShadow Dodgebuff.
    • Crystal Assassin armorCrystal Assassin armor has respectable defense and stat boosts, which makes this set a viable alternative to Hardmode ore sets. On Desktop version Desktop version, it provides a dash as part of its set bonus, allowing players to replace Shield of CthulhuShield of Cthulhu with another accesory.
    • Orichalcum armorOrichalcum armorOrichalcum armorOrichalcum armor provides very high critical strike chance and its set bonus can hit both eyes.
    • Palladium armorPalladium armorPalladium armorPalladium armor provides lower stat bonuses, but the Rapid HealingRapid Healing buff greatly increases natural regeneration.
    • Hallowed armorHallowed armorHallowed armorHallowed armorHallowed armor becomes a great choice if you have already defeated a Mechanical Boss. In the Desktop version it gives you the Holy ProtectionHoly Protectionset bonus, which allows to dodge some attacks.
    • Spider armorSpider armor is the best choice for summoners.
    • Obsidian ArmorObsidian Armor provides strong bonuses to whips, making it a strong alternative for summoners. The increased range and speed greatly increase the FirecrackerFirecracker's effectiveness, potentially outperforming the Spider Armor.
    • Monk's Bushy Brow Bald Cap.pngSquire's Great Helm.pngHuntress's Wig.pngApprentice's Hat.png The armor sets available from the TavernkeepTavernkeep combine summoning with one of the other classes. This is only available if you've defeated another mechanical boss.
    • Forbidden armorForbidden armorand Frost armorFrost armor() provide weak stat bonuses, but allow you to mix different damage types. On Desktop version Desktop version, the Frost armor provides excellent stat increases as a set bonus, making it a strong alternative to Adamantite or Titanium armors.


    For Melee users
    • The Shadowflame KnifeShadowflame Knife shoots very fast and deals a lot of damage per dagger. It also inflicts ShadowflameShadowflame, which deals 15 damage per second, more than any other debuff available. If aimed right, it can manage to hit both eyes at the same time.
    • Ice SickleIce Sickle could also be used, as Spazmatism will spend most of the time behind you, so shooting constantly backwards with the piercing projectile will hit him multiple times and deal quite reasonable damage.
      • Alternatively, Light DiscLight Discs can work too, if you already defeated The Destroyer or Skeletron Prime.
    • AmarokYoyos with the Yoyo Bag can be useful.
      • If you have already defeated another mechanical boss, using the YeletsYelets with the Yoyo Bag is very powerful.
    • Dao of PowDao of Pow and Drippler CripplerDrippler Crippler can be an excellent choice due to their high damage and range. However, they can be harder to acquire than other options available.
    For Ranged users
    For Magic users
    • Sky FractureSky Fracture is one of the strongest weapons mages can use in early Hardmode.
    • The Meteor StaffMeteor Staff and the Crystal SerpentCrystal Serpent are also very powerful choices.
    • The Spirit FlameSpirit Flame is a highly damaging weapon that is also consistent thanks to its homing properties.
    • The Shadowflame Hex DollShadowflame Hex Doll can also be very strong, despite its short range.
    • If you have Crimson, a good idea is to get the Golden ShowerGolden Shower, which is highly effective as it increases the damage greatly thanks to the Ichor (debuff)Ichor debuff, even when not used.
    • It's nice to have a Nimbus RodNimbus Rod, since the clouds can deal a good amount of damage if used properly.
    • If a Mechanical Boss has already been defeated, the Unholy TridentUnholy Trident is a powerful choice with confident aim.
    For Summoners
    • The Spider StaffSpider Staff is the best summoning choice because the spiders will latch on while they change forms, dealing hundreds of damage. Note that your arena will need to include background walls to make full use of the spiders.
    • The Sanguine StaffSanguine Staff is the best summoning choice for those who don't want to make a background wall arena, due to the bat's flying ability and high damage.
    • The Blade StaffBlade Staff's fast attacks and reliable targeting makes it a viable choice. They're at their fullest potential when boosted by Whips' Tag Damage.
    • The FirecrackerFirecracker can greatly increase the damage output of your summons, especially the Sanguine Staff. The DurendalDurendal is a excellent choice if you already have defeated a Mechanical Boss.
    • The Queen Spider StaffQueen Spider Staff also is worth running, as it doesn't count towards your total minions summoned.
    • If a Mechanical Boss has already been defeated, the Ballista CaneBallista Cane is a powerful choice when facing the Twins.


    Accessories that improve mobility are a must, since the Twins use quick attacks.

    • The Amphibian BootsAmphibian Boots, Frostspark BootsFrostspark Boots, or Terraspark BootsTerraspark Boots and Angel WingsWings are a must, especially for the Sky Bridge method. They allow the player to dodge, and also allow the player to flee temporarily if health is running low.
    • Even though it doesn't prevent Cursed Inferno, the Ankh ShieldAnkh Shield can still be used to prevent Knockback and for some useful extra defense.
    • An EmblemEmblemEmblemEmblemEmblem of your respective class is a must have in Hardmode because of its big damage buffs.
    • If playing in Expert mode, the Shield of CthulhuShield of Cthulhu is an incredibly useful item as well, with its dash being great for dodging.
    • The Expert-exclusive Worm ScarfWorm Scarf can greatly reduce damage taken.
    • The Brain of ConfusionBrain of Confusion is very useful for Expert Mode players with Crimson, as it provides a chance to dodge an attack . It doesn't prevent getting inflicted with the Cursed InfernoCursed Inferno debuff, however.
    • The Charm of MythsCharm of Myths provides a helpful boost to newer or slower players taking too much damage by reducing the cooldown of Potion Sickness as well as increasing passive health regeneration, it can also be used by quickswapping it from the vanity slot, since the effect only applies when consuming a Health Potion.
    • The Cross NecklaceCross Necklace or the Star VeilStar Veil are good choices, as the frequent charging attacks deal a lot of rapid damage, and the extra period of invulnerability mitigates a significant portion of this damage.
    • The Moon CharmMoon Charm is very helpful if you use Melee, as it will give a minor boost to all stats, raising your defense and therefore survivability, as well as giving higher damage.
    • The Magic CuffsMagic Cuffs (or Celestial CuffsCelestial Cuffs) are helpful if you're using Mana consuming items as you will take damage frequently from The Twins.

    If possible, reforge all Accessories for damage, crit chance or defense bonuses. If money is no object (see Guide:Making Money), having all Accessories reforged to Warding, Lucky or Menacing provides an extra 20 defense, 20% crit chance or 20% damage (24%, since the Demon HeartDemon Heart allows you to have 6 accessories, Desktop version up to 28% in Master Mode with 7 accessory slots).



    • Because the Twins are vulnerable to many debuffs, melee players as well as summoners can take great advantage of Flasks. The Flask of IchorFlask of Ichor greatly increases the damage output of all weapons, and the Flask of Cursed FlamesFlask of Cursed Flames(or Flask of FireFire if you're in a Crimson world) can give a very slight increase to DPS. Similarly, Spider minions can keep them afflicted with Venom, rangers can use Frostburn or other special arrows, and mages can use a Poison Staff or other weapons that inflict debuffs, such as the Shadowflame Hex Doll.
    • The Ice RodIce Rod is useful against Retinazer because the spawned ice blocks can block his lasers.
    • Always stick with a weapon, never use variety unless you are forced to.

    Specific Strategies[]

    Retinazer Cheese[]

    This strategy requires you take out Spazmatism first, once you defeat Spazmatism you need to get Retinazer into its second form. Then go inside a small box of solid blocks and use Summons (preferably with summon armor too), the Meteor Staff or the Daedalus Stormbow (preferrably with Holy Arrows and the Magic Quiver/its upgrades) to take down Retinazer. Because Retinazer does not charge in its second form and its lasers do not pierce blocks you will be completely safe.

    Close-ranged Unicorn Strategy[]

    A strategy that is helpful for players is a Skybridge using a Blessed AppleBlessed Apple and any kind of yoyo (A Yoyo BagYoyo Bag is recommended) or a long range weapon. Running with the Unicorn and shooting the yoyo behind you will deal a lot of damage and you won't get hit very much as the unicorn is slightly faster. Warning: Using this strategy may lead to the The Twins despawning if you go too fast.

    Minecart Strategy[]

    A strategy that is helpful for all classes is to use a minecart track extending as far as possible. For shorter minecart tracks, both ends can be hammered to allow the minecart to go in both directions without losing speed. As the minecart can go faster than The Twins, the player can use a long range weapon, such as a Repeater or a Yoyo (with Yoyo BagYoyo Bag) to deal damage from a relatively safe distance. Warning: Using this strategy may cause The Twins to despawn if that player travels too fast.

    Sentry Farming[]

    After gaining access to the Tier 2 equipment sold by the Tavernkeep, the fight becomes much easier to do. Wearing the Squire armor and using the Ballista Cane will give the best results because of the high defense and health regeneration provided by the armor, as well as the Ballista Panic! buff doubling the firing rate. Acquiring one of the accessories dropped by the Ogre is recommended for this method. When building your arena, be sure to use platforms whenever possible to maximize the opportunities your Ballistas have to fire. Make sure that you have Heart Lanterns and Campfires set up to give yourself the most health regeneration. Having a good pair of Wings, the Cobalt ShieldCobalt Shield or its upgrades, and the Lightning BootsLightning Boots, Frostspark BootsFrostspark Boots and Terraspark BootsTerraspark Boots are recommended for maximum mobility. The Summoner EmblemSummoner Emblem will make the fight go much faster, rounding out your accessories. A few Greater Healing PotionGreater Healing Potion are all the healing you'll need in case you get backed into a tight spot. Once the Twins have been summoned in, simply kite them around your Ballistas, taking damage periodically, preferably from Retinazer's laser for minimal damage. With the best Modifiers on your gear and all the relevant buffs, the Twins will go down in two to three minutes. If you find yourself taking too much damage and needing to heal more, consider swapping out the Summoner Emblem with a Charm of MythsCharm of Myths so you can heal more often.

    Invincibility Machine []

    Warning: Many players will consider invincibility machines as cheating.

    After beating up the Biome Mimics, you should have Fetid BaghnakhsFetid Baghnakhs and Daedalus StormbowDaedalus Stormbow. With two Target DummyTarget Dummies and a block overhead you can make the invincibility machine. Get a Slimy SaddleSlimy Saddle and try to bounce on both dummies while keeping it rapid. After you summon the boss, use the Fetid Baghnakhs to quickly take out Spazmatism. Then use the Daedalus Stormbow to beat Retinazer.

    Note: In the 1.4 update, this glitch was changed to be much harder to pull off, making it nearly impossible. Try this at your own risk, as it might not work.

    The Black Spot[]

    It is very easy to defeat The Twins with The Black Spot. The only thing you need is stable and high enough damage to beat them until dawn. Keep in mind that circling around in the skies may summon a Wyvern, so it's nice to have a weapon against segmented enemies, such as the Medusa Head.

    Note: The Black Spot was nerfed to be slightly slower, this may result in taking more damage than intended.

    Bouncing Strategy []

    It is very effective if you are able to keep The Twins low to the ground to bounce on them repeatedly using a Slimy SaddleSlimy Saddle. It works especially well to pair this with the Meteor StaffMeteor Staff, raining meteors down on whichever eye you happen to be bouncing on.