Guide:Eater of Worlds strategies

The Eater of Worlds (or EoW) is one of the 7 (or 8, counting King Slime) bosses in Terraria. Since the 1.1 update, this boss has gotten staggeringly easy to those players with Hallowed armor sets. Preparation is almost vital, especially for the newer players. The following are some hints, tips, and strategies to help you defeat it.

Terrain preparation
Like all Bosses preparing for the fight is probably the biggest factor in your success.

Standing on a wide, elevated platform (with either glass or sky below it) helps tremendously, especially with Spiky Balls added to it, but these tend to evaporate fairly quickly. Even without the Spiky Balls you can see him approaching from below, if you have a platform, even without it, Spiky Balls can still be useful. The Platform can be further upgraded with several levels of Wood Platforms, to further increase the player's mobility.

Since Worms cannot navigate in the air, this setup will drastically reduce the Eater of Worlds' maneuverability. In such a scenario, the Eater of Worlds can almost always be evaded; getting hit is often a result of the player's own risk-taking to deal extra damage. Currently, the Eater of Worlds can only be spawned and fought in the corruption. As such, it would be best to create an artificial corruption area to fight in. Alternatively, you can find naturally occurring Corruption and create a "stadium" there. However, if you plan to create a floating stadium, you may have to hollow out a large section of the Corruption to do it, as going too far above the Corruption will be considered exiting it, causing the Eater of Worlds to despawn.

If you are summoning Eater of Worlds by breaking Shadow Orbs, building a full-scale arena for every third orb or even trying to get all the way up to the surface is probably impractical. In that case, you will still benefit from taking time for terrain prep as shadow orbs are located in confined spaces and not being able to move around can get you trapped as Eater of Worlds circles around you. Bring your preferred tools for dealing with Ebonstone (Purification powder with a pickaxe and/or Bombs or Dynamite if its your first fight, and a Nightmare Pickaxe or better thereafter) and clear out any stone that impedes your movement. Give yourself a clear escape route out from where the Shadow Orb is, ideally to an open area with a good amount of horizontal clearance (there tends to be at least one intersecting the chasm above the shadow orb; if not, you should probably break out the Sticky Bombs and Dynamite to make one). Place Wood Platforms over deep water and any chasms that present a falling hazard. Smooth out large protrusions on the floor that will get in your way, especially if you're using Spiky Balls. In general, horizontal freedom of movement will likely be more important than vertical, especially as Eater of Worlds will be attacking you either through the ground or the ceiling. Light everything up well, and clear out any stray monsters from the area before breaking the orb. A Grappling Hook is pretty much required equipment in this scenario, and any items that well help you ascend up to your prepared area quickly, such as Rocket Boots, are good to have.

Armor and Accessories
Gold Armor is recommended but not necessarily needed, as it is not very hard to dodge the Eater of Worlds' attacks. Rocket Boots are recommended as they can help dodging. Accessories with Menacing or Warding will be most efficent here, but are not required.

Weapons
Because of its large size and multiple body parts, weapons that can deal damage to multiple sections should be used.

The Vilethorn will not deal damage as quickly as other methods, but will have a balanced damage distribution throughout the entire body. The Vilethorn is 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. Upon destroying the Eater's head, it will pause briefly while the body segment behind the head is converted into a head; aiming the Vilethorn directly at the head can destroy over a dozen segments in quick succession in this way.

Guns can be very effective at killing worms, particularly if Meteor Shot is used to pierce multiple segments. The Space Gun acts similarly, able to hit two segments in one shot. 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. The Demon Bow is relatively easy to get by this point and will work well. 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 in one hit when combined with the Necro Armor. It's a great weapon for future summons.

Non-explosive consumables, such as Shuriken and Throwing Knives, can be effective since their piercing attack will hit multiple segments while allowing the player to keep a safe distance. Spiky Balls are especially useful, as they can be thrown down where the Eater of Worlds is likely to surface, in the same manner as Vile Powder.

Flails can damage multiple segments and tend to damage the Eater of Worlds faster, but will also deal more focused damage, splitting the Eater of Worlds more often. They are excellent for killing smaller worms, though.

When using the Harpoon, if you can get it to attack you horizontally all from the same direction, the high firing rate of the harpoon will allow you to kill it without even being hit. To do this, make the EoW come at you horizontally, and shoot its head. This is very useful because it kills the EoW without splitting it into other worms, plus the head (with a much smaller health and defense) is easier to kill, turning the next body segment into an equally strong point to attack. Alternately, you can summon EoW at the bottom of a pit and using the grappling hook perch far enough up for him to come up at you vertically. The makes loot collection mildly more complicated but may easier to pull off than trying for the horizontal.

Another technique that uses the harpoon involves standing on a 2 block wide column with a box, grappling hook, or obsidian shield to keep you from falling off. Fire your harpoon at the floor underneath you. The EoW should charge straight up the column but get caught at the top. You will need some armor but you should get enough health from defeating segments to survive without too much difficulty.

Large swords like the Phaseblade, Blade of Grass and Fiery Greatsword can deal damage evenly if swung repeatedly at the long worm's arcing body. End-game non-hardmode weapons, like the Dark Lance and Night's Edge, can deal massive damage to multiple segments of the worm. By focusing attacks on the head, the next segment will already be weakened, likely falling in just one more hit. Because of the way the worm acts when its head is destroyed, it will quite literally feed itself into the meat grinder.

Dynamite will instantly kill any segments caught in its blast, providing an extremely fast (though extremely expensive) way to kill the Eater of Worlds. Grenades provide a more economical alternative, dealing high damage to several segments while also protecting the environment.

Water Bolt makes an interesting method of killing the worm, as it bounces around 3 times before disappearing. If you have sufficient mana, you can fill an enclosed space (which also protects you against other enemy spawns) with projectiles in this manner quickly. This causes a whole lot of fragmentation with the worm, and will likely get you damaged. On the plus side, it also kills the smaller segments very quickly. As every piece that is destroyed drops something, it may be worth killing as much as possible, rather than going all out and killing the whole thing (if it's very early in the game). You can acquire the water bolt without killing Skeletron if you can find one without having to go down into the dungeon. It is suggested you combine grenades with this method.

A Meteor Hamaxe can be a devastating weapon against EoW; Simply swing it as he comes by, and on only the second or third pass he'll be splitting into segments. This can be an easy and fast way of killing the EoW.

The choice of the weapon will essentially boil down to how safe you want play, or how fast you want to kill the Eater of Worlds.

The Aqua Scepter can be a good weapon against the EoW. It can be even more devastating with a Magic Power potion, and even more so with a Mana Regeneration Potion. The only downside to this is that these potions are difficult to obtain, and the Aqua Scepter can only be found in the dungeon, meaning you'll have to kill Skeletron first, and without the Mana Regeneration Potion, it uses Mana fairly fast.

One challenge known is to use the Ivy Whip to create a tripod while underground in the corruption shortly after breaking the third orb. This allows you to get an aerial advantage, but with limited view. Again, ranged weapons are best for beating the EoW, even in this position.

Potions
Healing Potions are recommended, just in case you slip up and do manage to get hit by the Eater of Worlds. They do not have to be in the hotbar as they are easily accessed using the hotkey for healing (default is 'h'). 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.

The Thorns Potion will damage the Eater of Worlds every time it hurts you and is easy to craft.

Managing the Worms
Killing a segment of the Eater of Worlds will split it at that point into two worms, with a new Head and Tail forming on either side of the destroyed segment. Of course, the more worms there are, the harder it is to dodge their attacks. A fundamental strategy when killing the Eater of Worlds is correct management of each worm. Avoid splitting worms when you can. If there are little worms, concentrate on killing those first, before returning to the main worm.

If you've summoned the Eater of Worlds by smashing three shadow orbs, then it is beneficial to fight the it from the small chasm that the last shadow orb came from because he is much easier to hit when confined to a small area. It is advised that you use at least silver armour and a light's bane sword or better.

Survival
Dying during a Worm fight will result in respawn at your spawn point. When you die, the Eater of Worlds will retreat, and you will not be able to fight him unless you summon him again. When summoned again, the boss will be back at full health, so caution is advised when fighting the boss. Health potions are also recommended as these will increase your lifespan, allowing more time to kill the Eater of Worlds.

"Surfing" the Worm
When using the above Platform scenario, and with proper movement, you can get the Eater of Worlds to chase you horizontally, as if it was surfing on your platform. This can be very useful once you are in the "Kill" phase of the fight, and to concentrate your fire on the Worms' Heads, which have less health than the Body. Using this strategy, entire sections of worms can be killed at once. The Ball 'O Hurt, Shurikens, or even a simple Gun, are all very effective. Note that it is much easier to get the Worm to surf by having a two Block wide platform.

End Game Simple Farming
The EoW can be a good source of gold if you sell the Demonite Ore, Shadow Scales, and Soul of Nights that it drops. (They can also, of course, be kept for crafting.) Either way, with end game armor and weapons, you can quickly defeat this easy-to-summon boss.

Hardmode weapons that swing continuously such as the Phasesaber and Excalibur are super-effective against the Eater of Worlds. If you have even Molten Armor, you will be able to take any damage the Eater of Worlds dishes out, as his killed segments tend to drop Hearts, which will heal you.

Flail Mechanics
If you have already obtained end-game equipment, you can easily farm the EoW by simply standing in one spot.

Since 1.0.6, flail mechanics were changed allowing you to hold the button down and let it swing freely. Using this new feature, you are able to farm EoW by sitting in one spot while standing on top of your flail. It is recommended you bring a Sunfury, although a Blue Moon or even a Ball O' Hurt will work if you have enough hearts and health potions. You can also use the Dao of Pow if you are in endgame and just farming him for the money. If you aren't using a Sunfury, bring with you an Ironskin Potion for the extra damage you will be taking. You should also bring a Cobalt/Obsidian Shield or a grappling hook to root you to one spot.

What you do is summon the EoW anywhere you prefer in the Corruption, and shoot your flail out. Hold the button so the flail is left out on the ground and stand on top of it. If you are using a grappling hook to root yourself to the ground, use it on top of the flail. Now, just sit back and relax as the EoW repeatedly runs into your flail ripping itself apart one part after another! If you're using a lower grade flail or armor, use your health potions if the hearts dropped aren't enough.

Then after it's finally dead, enjoy your effortless 15 gold!

No evasion farming technique
If the player has high enough defense rating and a powerful weapon, it's possible to kill the eater without moving at if they prevent knockback using either the grappling hook, Cobalt Shield or simply placing blocks around themselves. With a sufficiently high damage weapon capable of attacking multiple sections such as the Gold Broadsword or a very fast attacking high damage weapon such as the harpoon, the player will be able to survive the encounter relying on their initial health pool and heart items dropped from destroyed worm sections.

For this technique, having over 20 total defense is suggested. An Ironskin Potion with silver armor or gold armor would provide sufficient damage mitigation. Characters with low maximum health and weak weapons may find it difficult to survive long enough to start killing worm sections. In such cases, the player may want to consider a safe escape location to recover such as high altitude platforms. This technique allows defeating the eater very quickly, usually under a minute.

Spiked balls are very useful for this technique and fairly cheap. Throw down around 100 of them in a tight area around where you are standing, combined with a harpoon or vilethorn this can kill the boss in under a minute.