The Mechanical Eye is a consumable item that summons the boss The Twins anywhere in both pre-hard mode and Hard mode worlds, but must be used at Night. As of 1.2, this item has a small chance of dropping from any enemy entity in Hard Mode worlds.
Mechanical Eye Terraria HERO

Mechanical Eye Terraria HERO


  • The Twins are sometimes known to not appear after being summoned. (This is a very common bug on Multiplayer servers, but this could also be caused by an anti-boss spawning system used on a lot of servers)
  • If one attempts to use the Mechanical Eye (or the other mechanical summoning items) at dusk, the item will not be used (which is supposed to happen) but when that night begins the respective boss will spawn naturally. This is a way to summon the hard mode bosses without using the item.
  • Sometimes only one eye will spawn.
  • If summoned from high altitudes, The Twins may not appear.

The mechanical eye summons the twins, as shown above.

Update Info


  • Sprite change.


  • The drop chance was decreased from 1:1000 to 1:2500.


  • Added recipes.
  • The Mechanical Eye can be obtained by killing Hardmode enemies.


  • Added to the game.
Items Requiring Iron
Tools Chain · Iron Axe · Iron Hammer · Iron Pickaxe
Weapons Flamethrower · Iron Bow · Iron Broadsword · Iron Shortsword
Armor Iron Helmet · Iron Chainmail · Iron Greaves
Potions Ironskin Potion
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Other Empty Bucket · Inlet Pump · Iron Bar · Mechanical Eye · Mechanical Skull · Mechanical Worm · Minecart Track · Outlet Pump
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