The Hollow

"In the hollow sits a great castle made of brick as white as snow. It would make a great painting."

- The Painter
The Hollow is a Hard Mode good biome that is a counterpart of The Hallow and The Confection. This biome is based on control and depression, having pale grey trees and grass, a great tower with an eye in the middle of it watching over the biome and many solemn and sad looking enemies. The Underground Hollow can be found directly underneath a naturally generated hollow biome.

The Hollow does not exist in newly-generated worlds. It is generated along with a large Underground Hollow biome when the Wall of Flesh is defeated for the first time and the world converts to Hardmode. Once generated, Hollow spreads in a manner similar to Corruption, Poison or Crimson. Palestone, Palesand, White Ice and dirt blocks growing Hollowed grass will spread Hollow to neighboring blocks, causing Hollow enemies to spawn over ever-larger areas. Hollow can also be seeded in new areas via Hollowed Seeds, Sedated Water, or Grey Solution with the Clentaminator.

The Hollow (and its counterparts) is the only environment through which the Corruption, Poison and Crimson cannot spread at all, apart from the initial Hardmode conversion that takes place when the Wall of Flesh is defeated. The Dryad can tell the player the percentage of Hollow/Hallow/Confection and Corruption/Crimson/Poison in the world. Killing Plantera will slow the speed of the Hollow spreading.

Appearance (more detail)

 * In the background of The Hollow there is a greyish sky covered in clouds and occasional birds flying through. In the middle of the naturally generated biome there is a background tower made of white bricks with an eyeball in the top of it. This eyeball always watches the player, and the tower cannot be interacted with at all.
 * The Hollow consists of grey grass, trees have grey trunks and their leaves and white.
 * The water in The Hollow is all white and murky and constantly swirls. If your entire character is covred in the water, you will be given the Sedated debuff.

Enemies

 * Oddball Fairy
 * Tortured Unicorn
 * Gloople

At Night

 * Horned Eye
 * Blessed Eye

When Raining

 * Prison Slime

War Mode

 * Hollow Knight
 * Ooze Tower
 * Hollow Archer
 * Arrow Cloud
 * Ball of Depression

Underground Hollow

 * Hollowed Mimic
 * Pale Slime
 * Pale Bat
 * Pale Rat
 * The Awakened
 * Spoonbender
 * Enchanted Crossbow (NPC)

Hollow Desert

 * White Mummy
 * Blessed Mummy
 * Sedated Ghoul
 * Enslaved Jawfish

Hollow Snow

 * Hollow Pigron
 * Oddball Flinx

Bosses

 * The Dictator
 * Tower of Terror

From Terrain

 * Palestone
 * Palesand
 * White Ice

MORE TO BE ADDED
TBA