The Corruption



The Corruption is an ominous environment. It is best to explore this mid game where you have some of the better items (silver/gold items/armour). Purple corruption spreads over nearby dirt blocks, Grass blocks and trees, and Thorny Bushes sprout, making it a difficult land to traverse. Deathweeds can be found here. Purification Powder can be used on corrupted dirt to turn it into grass, and Hallowed Seeds can be placed to create The Hallow, which Corruption will not spread through.

Many chasms dot the landscape in the Corruption. It is recommended that you don't explore these until you have a Grappling Hook or some other form of vertical transportation, as chasms can be hundreds of feet deep. Chasms are covered in Ebonstone Blocks which can only be mined using a Nightmare Pickaxe or better, or by using Bombs or Dynamite, which also destroys Shadow Orbs. Alternatively, Purification Powder can be used to turn the Ebonstone into normal Stone Blocks which can be mined with any pickaxe.

Caves can often be found surrounding the chasms. In these caves, Pots, Chests And Life Crystals are common. Demon Altars are highly common in this environment.

Corruption vs. "The Corruption"

 * Corruption is a purple grass-like substance that infects grass blocks and spreads quickly to any connected Grass blocks, similar to ordinary grass.
 * "The Corruption" is a term used to describe the biome that takes effect when a significant amount of Corruption exists in an area of the World; theme music is changed in such areas (to The Corruption's theme), Trees turn purple, the sky darkens, and corrupted enemies like the Eater of Souls and Devourers spawn.

A small amount of Corruption can exist in other biomes, the same way Jungle Grass can exist in biomes that are not yet actual Jungle biomes, and Meteorite blocks can exist in biomes that are not Meteorite biomes. A multitude of any of these in an area will cause the respective biome to exist though, with altered theme music and spawned enemies appropriate to those environments.

Spreading Corruption
In normal mode, corruption can spread, but only under limited conditions:
 * Corrupt grass can spread in a manner similar to normal grass, converting adjacent dirt tiles with at least one side open to air (only in the Surface Layer)
 * Corrupt grass will grow over Hallow grass, and Hallow grass will grow over Corrupt grass. When the two meet, the results are unpredictable.
 * Corrupt grass can also displace normal grass, unless the grass has a Sunflower planted in it
 * Corrupt grass may sprout Thorny Bushes, which can spread corrupt grass according to the same rules

Naturally-occuring corruption will often be halted by various natural barriers (stone, desert, etc.) before it is even discovered, but care should be taken when creating an artificial corruption biome that it does not spread further than intended.

Hardmode Corruption
Once the Wall of Flesh is defeated, a world enters hardmode. New areas of corruption and hallow are immediately created that extend from the Underworld up to the Surface (sometimes going right through existing corrupt areas), and corruption begins spawning more dangerous monsters (in particular, the Corruptor and (underground) the Clinger).

Corruption spreads much more aggressively once the world is in hardmode:
 * Dirt and grass can still be converted to corrupt grass.
 * Mud and jungle grass can now also be converted corrupt grass (changing the underlying block type to dirt).
 * Stone can be converted to ebonstone.
 * Sand can be converted to ebonsand.
 * Sunflowers no longer block the corruption, and will be uprooted if the grass they are planted in is converted.
 * Corrupt grass is still limited to the Surface Layer, but ebonstone and ebonsand can spread through any depth.
 * Blocks that are up to three squares away from an existing corrupt block can be converted (even if incorruptible blocks are in the way).

In order to stop the spread of corruption in hardmode, the player needs to ensure there is a gap at least three squares wide containing no corruptible blocks (it can contain other blocks, such as wood, but still needs to be three spaces wide). The easiest way to do this is by creating hallow, since the hallow will spread according to similar rules and compete with corruption, but hallow also spreads aggressively and is only marginally less dangerous than corruption. (Also, keep in mind that you will need both corrupt and hallowed areas in the world to obtain all the new crafting materials you'll likely want.)

Note that the hallow is slightly more limited than corruption in its spread; in particular, it cannot spread through mud or jungle grass. If you'd like to preserve your natural jungle, surrounding it with hallow may be a good idea.

Corrupted Desert
When the Corruption spreads through desert, it becomes Corrupted Desert. It is very similar to the Corruption: the music theme is the same, the mobs are the same (except the Dark Mummy), and the background is just slightly different.

The sand is replaced by ebonsand. Although their color is different, cacti still drop cactus when cut, and waterleaves are also able to grow.

Getting through
The Corruption is infamous for being hard to get through. Here are a few pointers on making it through:
 * Defend yourself. Make sure you have at least Copper armor, or better yet, Iron armor. In Hardmode, Cobalt Armor or better is recommended.
 * Have good weapons. Ranged weapons are useful in taking out the Eaters of Souls and his closely related friends, especially if you use piercing ammo.
 * Don't fall down chasms. The deep Corruption chasms are a surprisingly large danger, so either get something to help you jump over, such as a Cloud in a Bottle, or get some blocks to make a bridge.
 * At the very least get a Grappling Hook.