Eater of Worlds

The Eater of Worlds is a pre-Hardmode Corruption-themed worm boss. It is summoned using Worm Food from within The Corruption or Underground Corruption, or by destroying 3 Shadow Orbs that spawn in Corruption worlds.

The Eater of Worlds is not a single target, but a string of segments with individual life counters. On the, it has a total of 50 segments, whereas on it has a total of 67 /  segments. When any inner body segment is destroyed, it splits into multiple smaller worms, each with their own head and tail. Each section of the Eater must be killed in order to defeat the entire boss. The Eater of Worlds, like all worms, is immune to lava.

Fighting the Eater of Worlds is the only way to obtain Shadow Scales, and it is one of the ways to obtain usable quantities of Demonite Ore. Individual segments drop some of these when killed, with a larger bonus drop upon defeating the entire entity. Defeating the Eater of Worlds allows the NPC to spawn, and on, since Meteorite can no longer blow up, allows the crafting of a Nightmare Pickaxe to mine it.

The Eater of Worlds is the Corruption counterpart to the Crimson's Brain of Cthulhu. The Hardmode mechanical boss equivalent to the Eater of Worlds is The Destroyer.

changes

 * In Expert Mode, the Eater of Worlds gains a % health increase. This brings its original Classic mode health of  /   health up to   /   health.
 * In Expert Mode, the Eater of Worlds periodically shoots Vile Spit projectiles from all body parts. These projectiles have a chance to inflict the Weak debuff onto the player for 10 minutes.
 * In Expert Mode, the Eater of Worlds takes 80% less damage from most explosives.
 * This damage reduction does not seem to apply to Bouncy Bombs.
 * It has a ~20% speed increase compared to normal mode.
 * When fought above the ground, the Eater of Worlds moves quicker and constantly fires Vile Spit at the player.

changes

 * All Expert Mode changes apply.
 * In Master Mode, the Eater of Worlds gains a % health increase. This brings its original Expert Mode health of  health up to   health.
 * The Vile Spit debuff duration is increased from 10 minutes to 12.5 minutes.

Tips

 * An effective strategy for fighting the Eater of Worlds is to hollow out the area in the Corruption and use piercing arrows (e.g. Jester's Arrows) and grenades.
 * Effective weapons include piercing or area-of-effect weapons, such as the Vilethorn, the Water Bolt, or Grenades, and fast melee weapons, such as the Falcon Blade and the or  Arkhalis.
 * Spiky Balls, purchased from the Goblin Tinkerer or dropped by Goblin Army enemies, can be thrown onto vertical arenas of platforms prior to the battle. Luring the Eater up into the Spiky Balls can deal damage to multiple segments at once.
 * Like other worm-types, once the Eater's head passes a given point, every body segment must follow. This allows the player to stand next to the body, attacking every segment as it goes by. The player should be wary of the head looping back around.
 * Killing Eater of Worlds head causes his speed to drastically decrease to almost stop.
 * If possible, try to aim for the head or tail of each section, as if they die first, the Eater will not split. Note that the head is far more vulnerable.
 * Using a Hook, it is possible to tank the Eater of Worlds by allowing the Eater to pass through the player and aiming for its head, quickly tearing the Eater apart while tanking any damage through the hearts dropped by the destroyed head segments.
 * If fighting in a chasm, be wary of getting surrounded, which can lead to death very quickly, especially in Expert or Master Mode. A quick way to escape is to have a bed to teleport to (using Recall Potions, Magic or Ice Mirror) over the battle area.
 * Farming the Eater of Worlds is particularly profitable, being one of the most effective ways of making money prior to Hardmode.
 * Converting the Demonite Ore to Bars, selling its drops will yield an average of per kill.
 * If Vile Mushrooms run short, Vile Powder (for Worm Food) can be bought from the Dryad during a Blood Moon.
 * Since each segment can drop loot when killed, it can be a good source of Presents during Christmas, and Goodie Bags, Bloody Machetes and Bladed Gloves during Halloween.
 * In Hardmode, it can provide other items as well:
 * It is a good way to farm for a Corruption Key/Mold, as every segment has a chance of dropping one.
 * In a Corrupt Snow biome, it can drop Amaroks, with each yoyo selling for a base value of.
 * In a Corrupt Ocean, it can drop Pirate Maps.
 * The Eater of Worlds will start to flee underground if the player leaves the Corruption biome, but will not immediately despawn. Players can utilize this mechanic to keep the Eater of Worlds away from themselves without despawning it by moving in and out of the Corruption, watching for the boss's icon on the minimap to make sure it does not leave.
 * The Slimy Saddle tends to be very effective, allowing the player to bounce on the Eater's segments while dealing damage. This can be somewhat harder to pull off in, due to the Eater of World's Vile Spit. However, keep in mind that the Slime Mount can bounce off of and destroy Vile Spit as long as you don't touch the ground.  Take care not to bounce out of the Corruption and cause the Eater of Worlds to despawn.
 * Using a flail will block any Vile Spit from hitting the player when is held down. Alternatively, a whip would also work for it can sweep a large area clean of vile spit in a single whip.

Trivia

 * The Eater of Worlds and Skeletron are the only bosses that do not have their own AI.
 * Skeletron only shares its AI with the Dungeon Guardian.
 * It might spawn outside of map boundaries on rare occasions when breaking Shadow Orbs, although the Eater of Worlds spawns in relation to the player, not the broken third orb.
 * The Eater of Worlds is sometimes abbreviated as "EoW".
 * It is immune to many debuffs, whereas its counterpart, the Brain of Cthulhu, is only immune to Confused.
 * The Eater of Worlds has 331 / eyes in total on the, and 246 eyes on other versions.
 * The Eater of Worlds will not despawn while in Crimson biome.