Bio
The Eater of Worlds is a pre-Hardmode Corruption-themed worm boss. It is summoned using Worm Food from within the Corruption and Underground Corruption, or by destroying 3 Shadow Orbs that spawn in Corruption-filled worlds. It can be summoned at any time of day. Do note that Eater of Worlds shoots vile spit in Expert and Master mode.

The Eater of Worlds is not a single target, but a string of segments with individual life counters. 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.

Spawn Conditions

It is summoned using Worm Food from within the Corruption and Underground Corruption, or by destroying 3 Shadow Orbs that spawn in Corruption-filled worlds.

Stratigies
• Eater of Worlds is a huge multi-segmented worm, and thus, its parts tend to linger for a while. You can attack its segments with penetrating weapons and arrows to deal a lot of damage. If a segment is destroyed, the Eater of Worlds will split into two different sections. This will continue until all segments are completely destroyed. Note that it can be difficult to hit if you choose to fight it in the Corruption's chasms, so it may be easier to lure it to the surface.
Beware that, when a segment dies, the segments in front and behind will detach and separately attack the player.
Managing the Split Worms
• When a segment is defeated, the Eater will split into two more worms that each follow the same attack pattern. These 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. However, the head is also the section that deals the most damage, so caution is advised. Alternatively, you can prioritize the tail segment, which is the opposite of the head (more Defense, less damage).
• 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.