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 player. 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.

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.

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.

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 it's head. This is very useful because it kills the EoW without splitting it into other worms. 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 in practice than trying for the horizontal.

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 manna, 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.

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.

Survival
Dying during a Worm fight will result in respawn at your spawn point. When you die, the Eater of Worlds will remain around the area around where you summoned him until you kill him, so, if you are a softcore or mediumcore player, placing a Bed near the battleground will be useful, since you will probably grab any items/coins you dropped upon death.

"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 and Shadow Scales that it drops, or you can keep them 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 superbly effective against the Eater of Worlds. If you have even Molten Armor, you will be able to tank 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.