Guide:Eater of Worlds strategies

"Screams echo around you..."

The Eater of Worlds (or EoW) is one of the bosses in Terraria. It is found in The Corruption. Preparation for this boss is both extremely helpful in the fight, and is relatively simple to complete. The following are some hints, tips, and strategies to help you defeat it when first encountered.

Spawn Conditions
Eater of Worlds is spawned by fulfilling one of these conditions:
 * Breaking three ;
 * Using.

You must then defeat Eater of Worlds within the Corruption: getting out of it will make it retreat and despawn.

The Fight
Eater of Worlds is a multi-segmented huge worm, and thus, its parts tend to linger for a while. You can damage those parts with penetrating weapons and ammos to deal a lot of damage. It is also very mobile if you decide to fight in Corruption chasm. Thus, it's important to reach the surface (and its arena if you made it, check below for more info).

Beware that Eater of Worlds, when a segment loses all the health, splits.

Managing the Worms
These 2 worms form a new head and tail, and they will make the fight more difficult. To prevent that, you can try to prioritize the Head segment, which has the lowest defense of the segments, but it is also the most damaging one. Alternatively, you can prioritize the Tail segment, which however is the opposite (more Defense, less damaging).

Careful management of segments can reduce the number of smaller, harder to hit worms. In this case, prioritize the use of non-penetrating weapons, and hit its head and tail. If you destroy a middle segment, concentrate on the smaller worm, since the larger one can be easy to predict and dodge.

Expert Mode
Eater of Worlds can shoot, and touching the worm itself causes debuff. And your explosives deal less damage against it, to the point to making them more expensive than its alternative throwing, equally-damaging, weapons.

Weak debuff can be annoying to deal, as you receive 3 more damage from all forms of damage.

Vile Spit can be hard to dodge if you decided to fight the worm inside the chasm, thus fight it on surface instead. However, Vile Spit's trajectory can be easily predicted: it has a fixed trajectory. You can easily dodge it if you constantly move.

Terrain preparation
The player must be in The Corruption to summon the Eater of Worlds; moving too far away from the biome during the battle will cause it to flee.

The Eater of Worlds is a very large Worm enemy, so dodging it may prove to be difficult. Make the arena fairly tall, thin, and easily climbable with many Platforms. That way, not only you can see it coming, but this will force it to climb in a relatively straight line, leaving large portions of its body exposed, and vulnerable to piercing attacks.

The above setup assumes the Eater of Worlds is fought on the Surface. If you are breaking Shadow Orbs, hollowing out an entire arena every third orb or escaping to a surface arena may not be practical; you should still modify the terrain around you to have a clear path of escape from the chamber where the Orb is located and ideally, easy access to a cleared space with good horizontal clearance and any hazardous terrain smoothed out or boarded over.

Armor and Accessories
Gold armor, Meteor armor (with the Space gun), or Platinum armor is recommended.

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

Rocket Boots are recommended as they can help dodging.

Accessories with Menacing or Warding will be most efficient here, but are not required.

Weapons
For Melee users:
 * Large swords like the Phaseblade, or the War Axe of the Night can deal damage evenly if swung repeatedly at the long worm's arcing body.
 * The Chain Knife is also a great weapon to kill the boss, but takes a while to kill it. If you have a Ball O' Hurt from breaking Shadow Orbs, or a different flail, you can easily swing it into the EoW and inflict massive damage to many of its segments. This method requires more defense and/or health however, and preferably a way to avoid knockback.
 * If you are lucky enough to find an Enchanted Sword Shrine and obtained an Arkhalis, you may find them very effective against it.

For Ranged users:
 * Guns can be very effective at killing worms, particularly if Meteor Shot is used to pierce multiple segments.
 * The Musket does 33 damage and is easily obtained by breaking Shadow Orbs and is a great gun to get for killing the Eater of Worlds.
 * The Harpoon is a excellent choice of weapon, but it works best close to the Eater of Worlds and requires the Goblin Army to be defeated first.
 * Bows don't have as fast a rate of fire, but by farming Devourers for their teeth and upgrading to Unholy Arrows, the piercing effect makes them a great choice.
 * Jester's Arrows work just as well, if not better, and are fairly easy to get.
 * The Demon Bow is also relatively easy to get by this point and will work well, but even the Platinum Bow can be used. If a shot can be lined up, about 30 damage can be done to 10 segments, finishing the fight very quickly.
 * The Star Cannon, while very expensive, yet still obtainable for your first encounter, makes a mockery of it, ripping through multiple segments and destroying virtually any segment in one hit.

For Magic users:
 * The Vilethorn will not deal damage as quickly as other methods, but will have a balanced damage distribution throughout the entire body. It's obtained from Shadow Orbs in the Corruption. Furthermore, this is a relatively safe weapon to use against the worm as it can be deployed in the worms path and will remain for a short time doing damage while giving you time to dodge.
 * Water Bolt can also be used if you were lucky enough to find one in the entrance of the Dungeon. In confined spaces, the water bolts can ricochet many times and deal tremendous amounts of damage.
 * Ruby or Diamond Staff can also pierce multiple parts and deal great damage, while using little mana.
 * Also, a Bee Gun can be very effective against the Eater of Worlds, because of its fast-rate homing bees, and can be further enhanced with the Hive Pack, for Expert players.

For Throwing users:
 * Non-explosive consumables, such as Shuriken and Throwing Knives, can be effective since they penetrate segments, meaning that they hit multiple times while allowing the player to keep a safe distance.
 * Explosive consumables, like Grenades and Beenades are very effective, killing all pieces caught in the blast. The player should be careful, however, to not get caught in the blast themselves.
 * Spiky Balls are especially useful, as they can be thrown down where the Eater of Worlds is likely to surface.
 * Molotov Cocktails are extremely effective against the Eater of Worlds, leaving behind multiple flames on the ground that do ~40 damage each and hit every segment that moves through them.

Potions

 * Ironskin and Regeneration Potions can really help mitigate any hits you take.
 * Hunter Potions can be very useful in spotting the Eater of Worlds as it burrows, making it easier to fight even without a raised platform.
 * Last of all a Bowl of Soup, Cooked Marshmallow, Pumpkin Pie or Cooked Fish will also give you a small additional buff.
 * The Thorns Potion will damage the Eater of Worlds every time it hurts you and is easy to craft.
 * An easy way to get out of the chasm if you wish to fight on the surface is to use a Gravitation Potion and a Lucky Horseshoe.

Farming
The EoW can be a good source of money if you sell the and  that it drops. With endgame armor and weapons, you can quickly defeat this easy-to-summon boss.

Hardmode weapons that swing continuously such as the Phasesaber and Excalibur are extremely effective against the Eater of Worlds. Spears and higher tier Flails can also quickly dispose of the EoW. Simply grapple yourself to the ground (or use a Cobalt Shield) and keep attacking/keep your flail below you by holding. If you have Molten Armor, you will be able to take any damage the Eater of Worlds dishes out, as its killed segments tend to drop Hearts, which will heal you.