Guide:Mechdusa strategies

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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: Under revision (This Guide is currently being revised or has been revised partially. It hasn't met all quality standards yet.)
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Desktop/Console/Mobile-Only Content: This information applies only to the Desktop, Console, and Mobile versions of Terraria.
MechdusaHardmode exclusive
Classic mode icon.png Classic
Expert mode icon.png Expert
Master mode icon.png Master
  • Item (Quantity)Rate
  • Waffle's IronWaffle's Iron(Desktop, Console and Mobile versions)
Retinazer Trophy.png Skeletron Prime Trophy.png"What a horrible night to have a curse."Destroyer Trophy.png Spazmatism Trophy.png

Mechdusa is an early Hardmode boss exclusive to Get fixed boi worlds which is composed of all three mechanical bosses. It is essentially a forced triple boss fight.

Spawn Conditions

Mechdusa can only be spawned in a world with the secret seed Getfixedboi, and when one or more of the following conditions are met:

The Fight

The Mechdusa is three separate bosses merged into one, all of which must be defeated. They have a combined health of 256,800 / 327,420 / 436,560, shared between them. Those bosses are Skeletron Prime, The Destroyer, and The Twins.

When the Mechdusa spawns, the bosses are all connected together. Skeletron Prime is the one holding them together; while it is alive, the other parts will move together with it rather than following their usual behavior.

While the Twins are attached to Skeletron Prime, Retinazer will generally stay to the left while Spazmatism will generally stay to the right. This can be useful when trying to avoid their attacks; for instance, phase two Spazmatism is less likely to hit players who stay on the left.

General Strategies

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(Desktop, Console and Mobile versions) will provide a significant defensive boost. Garden GnomeGarden Gnomes(Desktop, Console and Mobile versions) and (Desktop, Console and Mobile versions) (if underground) proper torch placement will reduce damage taken and increase damage dealt due to the luck. The Torch God's Favor(Desktop, Console and Mobile versions) helps with this. HoneyHoney pools can also be used for extra health regeneration.
  • (Desktop, Console and Mobile versions) SunflowerSunflowers provide the Happy!Happy!(Desktop, Console and Mobile versions) buff to nearby players, 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 Lesser Healing PotionLesser Healing Potions or HoneyfinHoneyfins. On the Desktop version Desktop, Console version Console, and Mobile version Mobile versions, Restoration PotionRestoration Potions are healing potions with a shorter cooldown.
  • 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(Desktop, Console and Mobile versions) 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 1 Second Timertimers to activate them infinitely.
  • In Hardmode, the Brand of the InfernoBrand of the Inferno(Desktop, Console and Mobile versions) and Sergeant United ShieldSergeant United Shield(Desktop, Console and Mobile versions) can be used to parry incoming contact damage.
  • 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(Desktop, Console and Mobile versions), Ammo BoxAmmo Box(Desktop, Console, Old-gen console and Mobile versions), Crystal BallCrystal Ball, Bewitching TableBewitching Table(Desktop, Console and Mobile versions), War TableWar Table(Desktop, Console and Mobile versions), and Slice of CakeSlice of Cake(Desktop, Console and Mobile versions) before you go to explore or battle bosses/invasions. These will give boosts that are useful to have, with the first five being class-specific. They give SharpenedSharpened(Desktop, Console and Mobile versions), Ammo Box (buff)Ammo Box(Desktop, Console, Old-gen console and Mobile versions), ClairvoyanceClairvoyance, BewitchedBewitched(Desktop, Console and Mobile versions), StrategistStrategist(Desktop, Console and Mobile versions), and Sugar RushSugar Rush(Desktop, Console and Mobile versions), respectively.

Terrain Preparation

It's important to have plenty of room for this fight. Fighting aboveground gives more room, but on the Getfixedboi seed this has the disadvantage of increased enemy spawns, while the lower gravity can be helpful or harmful depending on how high you are and your movement strategy. Alternatives include blowing up a large underground arena using Dynamite, or creating a very long minecart track.

If players cannot deal with the low gravity, the next largest open space is the region between the Underworld spawn island and the ruined houses. This can be done on either side, whichever one is more convenient. Players will need a lot of dynamite (get 300 for starters).

An Underworld arena for fighting Mechdusa.

1: Dynamite the blocks in the lava. This causes the lava to sink, giving players more vertical space. If the player wants to sink the lava even more, dynamite the bottom of the spawn island.

2: Place rows of a lava-resistant platform, (Underworld enemies drop lava when killed in this seed) as it suits the player.

3: Players can use a Lava Walking item (Water Walking Potion, Lava Waders, etc.), or build a row of blocks or platforms above the lava. If the player chooses blocks, players can dig a hole every few blocks to allow the lava to pass through. Players can fill the holes with platforms to make sure Guide Voodoo Dolls do not fall into lava.

4: If players place Campfires and such, campfires burn when lava touches them. Players can use Bubble Blocks to partially mitigate this.

5: If the player still desires more vertical space, the top of the Underworld can be easily destroyed using Sticky Dynamite.

6: Remember to keep a lava immunity item during the fight, as players might touch the lava of an enemy that died. An Obsidian Skin Potion is recommended as it doesn't require an accessory slot.

The space isn’t as large as the surface, but players won’t accidentally die from going off the top of the map.

Asphalt Blocks are available from the beginning of the game since the Steampunker spawns early as feature of the Getfixedboi seed, although she dies after the first day and does not respawn again until at least one part of Mechdusa is defeated. Two rows of blocks widely spaced apart can serve as an arena, using Gravitation Potion to switch between them.

Gearing Up


  • Adamantite armorAdamantite armorAdamantite armorAdamantite armor provides the overall greatest increase to all stats, though it lacks a unique set bonus.
    • Frost BreastplateFrost Breastplate can be substituted onto melee and ranged variants of Adamantite armor for better offensive and defensive stats, as the set bonuses are less important. Mythril GreavesMythril Greaves/Spider GreavesSpider Greaves can also be substituted in for even more offensive stats.
  • Titanium armorTitanium armorTitanium armorTitanium armor is a great choice due to its high stats and the Titanium BarrierTitanium Barrier buff.
  • Crystal Assassin armorCrystal Assassin armor provides respectable defense, stat boosts and a nice dash that can free an accessory slot usually used for the Shield of CthulhuShield of Cthulhu, making it a viable alternative to Adamantite armor or Titanium armor.
  • Orichalcum armorOrichalcum armorOrichalcum armorOrichalcum armor is especially powerful as its set bonus can hit many parts of Mechdusa.
  • Palladium armorPalladium armorPalladium armorPalladium armor provides lower stat bonuses, but the Rapid HealingRapid Healing greatly increases natural regeneration, which can help with this long fight.
  • Spider armorSpider armor is the best choice for summoners. However, if one desires extra range for whips like FirecrackerFirecracker or the Cool WhipCool Whip, Obsidian armorObsidian armor may be useful.
  • Forbidden armorForbidden armor provides weak stat bonuses, but comes equipped with a set bonus that can be used against the Destroyer portion of Mechdusa to great effect.
  • Frost armorFrost armor can apply Frostbite against all portions except the Destroyer, and great stat increases are part of the set bonus, which makes it a good alternative to Adamantite and Titanium armors.


Mechdusa is very large and has many different components that can be damaged, so weapons with an area or piercing effect have a strong advantage at the beginning. Due to the different nature of the bosses that make it up, you may need to switch out weapons as the fight progresses, such as switching to single-target damage once the Destroyer portion dies.

For Melee Users
  • Drippler CripplerDrippler Crippler has a piercing projectile that can do high damage while maintaining some distance from the boss.
  • The Shadowflame KnifeShadowflame Knife is a powerful choice due to its ability to bounce multiple times off of Mechdusa, hitting several parts.
  • The Sergeant United ShieldSergeant United Shield is another strong choice due to its ability to home and hit multiple parts of Mechdusa.
For Ranged users
For Magic users
  • The Orange ZapinatorOrange Zapinator has a special property that randomly multiplies damage when it pierces enemies. Since the Mechdusa has many parts, individual lasers from the Zapinator can have damage multiplied ten times or more. Once there are only a few parts of Mechdusa left, though, it would make sense to switch to another option.
  • The Nimbus RodNimbus Rod and Clinger StaffClinger Staff have powerful piercing properties that can do heavy damage to the Destroyer portion of Mechdusa.
  • The Golden ShowerGolden Shower does excellent piercing damage and inflicts the Ichor (debuff)Ichor debuff on several parts of Mechdusa, allowing your other weapons to deal even more damage.
  • The Cursed FlamesCursed Flames does high damage and inflicts the Cursed InfernoCursed Inferno debuff.
For Summoner users
  • The FirecrackerFirecracker and Cool WhipCool Whip are the best whips for this fight, with the former multiplying enemy damage and the latter having a snowflake projectile that pierces multiple segments and hits probes.
  • The Sanguine StaffSanguine Staff has consistent attacks and deals well with Probes. It is one of the strongest summons available for this fight.
  • The Blade StaffBlade Staff is another viable option, but is much stronger when used with a whip that has Summon Tag damage, such as the Cool Whip.


  • Accessories that increase your mobility such as the Lightning BootsLightning Boots or wings are a must if not using a mount.
  • An Emblem for your class will increase your damage output significantly.
  • The Frog LegFrog Leg (and its upgrades) makes all wings significantly faster, which helps when dodging its attacks.
  • The Charm of MythsCharm of Myths increases your base health regeneration and reduces the cooldown on potions, making it a good choice if you have trouble dodging its attacks.
  • The Cobalt ShieldCobalt Shield or its upgrades make you immune to knockback which is useful if you find yourself getting knocked around during the fight.
  • The Shield of CthulhuShield of Cthulhu can greatly increase your mobility as well as provide some extra defense.
  • The Worm ScarfWorm Scarf and Brain of ConfusionBrain of Confusion will reduce damage taken, making them powerful choices. In addition, the Brain of Confusion can grant some additional damage.
  • The Star VeilStar Veil can add additional immunity time from hits and can also deal extra damage.


Specific Strategies


The despawn ranges for the parts of Mechdusa are not equal. By moving far enough away from the main body, it is possible to despawn everything except the Destroyer. By killing just this part, the player can access some post-mech gear such as Hallowed Armor or Old One's Army weapons.


A long minecart track can be an efficient way to fight this boss, as many attacks will miss if the player is going fast enough. In the Get fixed boi seed, a minecart in hell is especially useful as Retinazer and Skeletron Prime's Laser arm can get stuck in the ceiling, being unable to fire for part of the fight.

As mentioned above, parts of Mechdusa will despawn if the player moves too far away, so go faster to despawn parts or slower to keep them together. Turning around can be accomplished with pressure plate tracks, teleporters (space a screen or two apart so as not to run into the body of Mechdusa), and hammered minecart tracks to reverse direction.