The Eater of Worlds is one of the seven pre-Hardmode bosses. It can only be fought in the Corruption, where it's summoned either by destroying three Shadow Orbs or by using Worm Food (either method is repeatable).
The Eater of Worlds uses the same AI as all of the other monsters in the Worms Family. However, unlike other worms, every individual segment has its own health. If you destroy a segment that is neither head nor tail, the Eater of Worlds splits at the spot that was destroyed and each half will continue fighting.
- There needs to be at least 500 Ebonstone Blocks nearby in order to be considered inside a valid Corruption area for the purposes of fighting this boss. For this reason, it is recommended to fight it in a horizontal chasm.
- From patch 1.0.5 and onwards, the Eater of Worlds would flee after a while if the player wasn't in a corrupt area. Until patch 1.0.6, the player would get the message "Eater of Worlds was defeated.", but now the message says "Eater of Worlds flees."
- When summoned in the Underground corruption after the Wall of Flesh has been defeated, it's a great source of Souls of Night due to its many parts. This method can also be used to farm Corruption Keys.
- If the section directly behind the head or directly in front of the tail is killed, both sections will die and drop loot separately. The same happens when the boss itself is shortened to two segments, at which point killing either of them is counted as a defeated boss, and the other section disappears.
- When displayed on the Mobile Edition minimap, there is no skull icon to indicate a boss, but there will instead be a separate white circle to indicate a normal entity for each segment. This also happens for other worm type enemies.
Disclaimer: For the purposes of this guide, it's assumed that the player is using a new character in a new world, and would therefore only have access to appropriately-tiered equipment. Otherwise, this boss would be a piece of cake.
The head has 65 and 0 defense, the body segments have 150 and 2 defense, and the tail has 220 and 4 defense. In order to function as a monster, each part of the Eater of Worlds needs to have at least two pieces: a head and a tail. If one of the sections of the boss ever has less than that, then the entire section dies. Because of this, destroying every other segment of the boss is the most efficient way to defeat it (though not always the most practical).
Whenever the Eater of Worlds splits, damage to each part remains. Therefore, trying to maximize damage equally across the entire body will generally result in the fastest kill.
Because the head deals so much damage, it's strongly recommended that you avoid it at all costs, even if it means having to move through the boss's body segments (taking damage in the process). Also, it may be a good idea to aim for the head, as not only does it have less defense and HP than a body segment, but splitting the boss up by destroying body segments will only make it more difficult to dodge its attacks. (Focusing on the head should also increase the amount of loot dropped.) When the head is destroyed, the boss will stall for a bit, allowing you to take aim and fire at the new head. If the player is using one of the above recommended weapons, then it's possible for the player to stall the boss this way almost indefinitely, leading to a quick, easy kill.
It's ill advised to fight the Eater of Worlds inside a chasm, as not only can it strike with little warning, but it could also knock you to your death. You could use the Grappling Hook to cling onto a wall, though you should still avoid getting struck by the head as, again, it deals heavy damage to players.
If you don't want to fight the EoW by breaking a shadow orb, but don't have enough Rotten Chunks to make Worm Food you can start building an arena above ground. Just kill any corruption monsters and take the rotten chunks they drop and once you have the arena ready, you should also have enough rotten chunks.
Since this boss is composed of multiple segments that each have their own HP, weapons that can hit multiple enemies per attack are recommended. These include the Vilethorn, any kind of flail (such as the Ball O' Hurt) and a bow (preferably a Golden Bow or better) with Unholy Arrows, though a Gold Broadsword or better can be used if none of these are available. The Harpoon is also highly useful against this boss, since it's more than capable of striking multiple segments on his body at once if the player stands close enough.
Silver Armor or better is recommended, as well as having at least 200 . Bring along a few (Lesser) Healing Potions as well, as the head deals a massive 40 damage (minus armor), though the body segments deal only 15 damage by comparison.
The following optional Consumables may also be of some use during this boss battle, if you're willing to use them that is:
Since this boss can only be fought in the Corruption, your arena will need to either be located in the Corruption, or be made out of enough Dirt Blocks covered with corrupted grass and/or Ebonstone Blocks (500 blocks should do the trick) for the game to determine that it lies within a valid corrupted area. The arena doesn't have to be very big (around 75 blocks is a nice width), though it should have a roughly flat surface at the bottom, and at least 2 rows of wooden platforms for avoiding the Eater of Worlds should it decide to swim along the surface of the bottom floor, or one of the rows of wooden platforms. If you'd like, you can dig some holes beneath your arena (and to the sides and above it if it was built underground) to more easily spot the Eater of Worlds before it attacks.
If you built your arena above ground, then you may have to deal with it becoming tangled up more often, as the boss doesn't have much earth to swim around in. However, if you built your arena partially or even fully underground, then the boss shouldn't tangle up as much, and can easily be set up for a quick kill (as mentioned before), though you will have to keep an eye on every side of your screen, as the boss can burst from the walls, or (if deep enough underground) even the ceiling.
- This boss could possibly be a reference to the "Eater Of Worlds" from Stephen King's novel "Night Shift" from the first short story "Jerusalem's Lot".
- This boss could be a reference to the 1990 film `Tremors` where giant worms with teeth attack a group of friends.
- This boss could be a reference to Alduin from Skyrim, as Alduin is often referred to as "The Worm" and "World-Eater".
- The way this boss splits into more Eaters of Worlds could be a reference to the classic arcade video game "Centipede"
- In the iOS version of Terraria, once you break the third shadow orb, the entire Eater of Worlds will spawn in the location of the shadow orb, and the message "Eater of Worlds has awoken!" will not display. "Eater of Worlds has been defeated!" will still display once it has been killed, however.
- Rarely, the boss will spawn as only a single segment, and nothing else. It will function the same as normal, but it's very ineffective at killing anyone.
- A possible bug may be that, when building over the Corruption, the boss will be summoned, as if incredibly displeased with the bridge, leading to much confusion and claims of griefing.
- One very specific bug may happen if the Eater of Worlds is fought in the Underground Jungle. Some of its segments may get "chained/fused" with a Man Eater and stand still.
- Another bug is that the boss will be summoned on world creation (i.e. make a world then enter it). This is most likely caused by defeating a boss and then immediately creating the new world.
- Sometimes when a Meteorite lands and you exit the world and re-enter it the boss will be summoned.
- Another possible bug is when you've cut the Eater of Worlds into several segments and one kills you, that worm will disappear but the others will continue to fight.
- Sometimes, on console version, on a full server, only one segment will be visible, and only it can be damaged. Once destroyed, the next segment will become visible.
- If you break 3 Shadow Orbs, and use Worm Food, it will summon 2 Eater of Worlds (confirmed).
- Eater of Worlds now drops the Eater Of Worlds Mask.
- Eater of Worlds has chance to drop Blend-O-Matic (Bug).
- Eater of Worlds now drops the Eater of Worlds Trophy.
- Now says "Eater of Worlds flees" when outside of corruption.
- No longer drops Shadow Armor and will flee if outside of corruption.
- Added to the game.