Layer

Layers are various regions contained within Planets and Moons. Biome distribution determines the way that each layer is generated within a world. Each biome generally contains a set of blocks for terrain, a list of Monsters that can appear in the biome, their status effects - such as immunities - microdungeons, plants, and other ground decoration, among other factors. In addition, each layer always contains one primary biome and a varied number of optional secondary biomes; both primary and secondary biomes can contain sub-biomes, especially in the surface layer. For example, several underground biomes appear within generic underground layers, as opposed to composing the main biome of those layers themselves.

Layers have several properties that are defined by their main biome. For example, each layer has two sets of Music Tracks that are associated with it: one set for daytime and one set for nighttime. Many layers use the Day Tracks during the day and the Night Tracks during the night. However, many layers use different sets of tracks, such as the surfaces of mutated and scorched planets.

In addition, the main biome of a layer determines its background. The main surface biome also appears to determine the sky color for all layers of the planet and environmental status effects.

It is important to remember that biomes are parts of layers, not the layers themselves. Although surface layers' biome distribution generally depends on the type of the world, the biomes of most other layers, such as the underground layers, can appear on almost any kind of planet.

Layer Types

Layers appear at specific heights on a planet, and are sorted based on where they appear.

Highest

• Space: Layers of this type are the top layer of a planet. Space layers have no air, requiring the player to use a Breathing EPP or better when making prolonged expeditions to these layers. All space layers are populated with asteroids made of Meteorite Rock and Magmarock.
• Atmosphere: Layers of this type are located in between the space layer and the surface. Atmosphere layers have no solids or liquids in them, only air.
• Surface: Layers of this type are where the solid part of the planet begins. All surface biomes belong in this layer type, making this the most diverse of all the layer types.
• Subsurface: Layers of this type occur just beneath the surface layer. The ocean floors of Ocean, Toxic, Arctic and Magma planets are considered subsurface layers. Below this layer, Survival mode and Hardcore mode characters cannot beam up, even without blocks behind them.
• Shallow Underground: Layers of this type are found just beneath the subsurface layer. Tarpit, Mushrooms, Wilderness and Mini Village are found in layers of this type.
• Mid Underground: Layers of this type are found between the shallow underground and deep underground layers. Luminous Caves, Stone Caves, Bone Caves and Ice Caves are found in layers of this type.
• Deep Underground: Layers of this type are found just above the core layer. Cell Caves, Flesh Caves, and Slime Caves are found in layers of this type.
• Core: Layers of this type are the bottom layer of a planet. Generally, no monsters appear in core layers.

Lowest

Default Planetary Composition

Most planets follow the default guidelines for layer composition, outlined below:

• Space: Asteroids
• Atmosphere: Atmosphere
• Surface: Depends on planet type
• Subsurface (ocean-type planet): Depends on dominant ocean-type biome
• Subsurface (non-ocean-type planet): Underground 0a, Underground 0b, Underground 1a, or Underground 1b
• Shallow Underground: Tarpit, Mushrooms, Wilderness, or Mini Village; Underground 0a, Underground 0b, Underground 1a, or Underground 1b
• Mid Underground: Luminous Caves, Stone Caves, Bone Caves, or Ice Caves; Underground 0c, Underground 1c, Underground 1d, Underground 3a, Underground 3b, Underground 3c, or Underground 3d
• Deep Underground: Cell Caves, Flesh Caves, or Slime Caves; Underground 0d, Underground 5a, Underground 5b, Underground 5c, or Underground 5d
• Core: Blaststone Core Layer, Magmarock Core Layer, or Obsidian Core Layer

List of Layers

Space Layers

Layers at this height use the Night Tracks during the day as well as during the night.

Asteroids
Primary Material	Meteorite Rock
Secondary Material(s)	Magmarock
Liquid	None
Ore Distribution	Asteroid
Monster(s)	Skimbus

Barren Asteroids
Primary Material	Meteorite Rock
Secondary Material(s)	Magmarock
Liquid	None
Ore Distribution	Asteroid
Monster(s)	None

Atmosphere Layers

Layers at this height have no Music Tracks.

Atmosphere
Primary Material	None
Secondary Material(s)	None
Liquid	None
Ore Distribution	None
Monster(s)	Large Flying Monsters, Passive Small Flying Monsters

Void
Primary Material	None
Secondary Material(s)	None
Liquid	None
Ore Distribution	None
Monster(s)	None

Surface Layers

See Biome.

Subsurface Layers

Ocean Floor
Toxic Ocean Floor
Arctic Ocean Floor
Magma Ocean Floor

Desert Subsurface
Primary Material	Sandstone
Secondary Material(s)	Dry Sand Loose Silt
Liquid	Oil
Ore Distribution	Depth 2
Monster(s)	Small Aggressive Biped or Quadruped, Snaggler, Crustoise, Peblit, Snaunt, Spookit

Shallow Underground Layers

Tarpit
Mushrooms
Wilderness
Mini Village

Mid Underground Layers

Luminous Caves
Stone Caves
Bone Caves
Ice Caves

Underground 0c
Primary Material	Cobblestone
Secondary Material(s)	Rock 20 Dry Sand
Liquid	Water
Ore Distribution	Depth 2
Monster(s)	Small Aggressive Biped or Quadruped, Pulpin, Batong, Miasmop, Wisper, Lilodon, Snaunt

Underground 1c
Primary Material	Mud
Secondary Material(s)	Rock 12
Liquid	Water
Ore Distribution	Depth 2
Monster(s)	Small Aggressive Biped or Quadruped, Lumoth

Underground 1d
Primary Material	Sandstone
Secondary Material(s)	Dry Sand , Loose Silt
Liquid	Water
Ore Distribution	Depth 2
Monster(s)	Small Aggressive Biped or Quadruped, Snaggler, Crustoise, Peblit, Snaunt, Spookit

Underground 3a
Primary Material	Rock 02
Secondary Material(s)	Grassy Rock Ice
Liquid	Water
Ore Distribution	Depth 2
Monster(s)	Small Aggressive Biped or Quadruped, Petricub, Crutter, Batong, Smoglin, Bobfae

Underground 3b
Primary Material	Rock 14
Secondary Material(s)	Rock Bricks Stone Rubble
Liquid	Water
Ore Distribution	Depth 2
Monster(s)	Small Aggressive Biped or Quadruped, Scandroid, Oculob, Fennix, Voltip, Crustoise

Underground 3c
Primary Material	Ice
Secondary Material(s)	Snow Slush
Liquid	Water
Ore Distribution	Depth 2
Monster(s)	Small Aggressive Biped or Quadruped, Lilodon, Wisper, Pulpin, Skimbus, Petricub

Underground 3d
Primary Material	Rock 17
Secondary Material(s)	Crystal Block Stone Rubble
Liquid	Water
Ore Distribution	Depth 3
Monster(s)	Small Aggressive Biped or Quadruped, Wisper, Pyromantle, Ignome, Fennix, Pulpin

Deep Underground Layers

Cell Caves
Flesh Caves
Slime Caves

Underground 0d
Primary Material	Mud
Secondary Material(s)	Wet Dirt Cobblestone
Liquid	Water
Ore Distribution	Depth 3
Monster(s):	Small Aggressive Biped or Quadruped, Squeem, Snaunt, Oculob, Agrobat, Miasmop, Snaggler

Underground 5a
Primary Material	Rock 04
Secondary Material(s)	Rock 15
Liquid	Water
Ore Distribution	Depth 3
Monster(s)	Small Aggressive Biped or Quadruped, Crustoise, Tintic, Oculob, Spookit, Petricub

Underground 5b
Primary Material	Rock Bricks
Secondary Material(s)	Copper Gear Block Rock 17
Liquid	Water
Ore Distribution	Depth 3
Monster(s)	Small Aggressive Biped or Quadruped, Scandroid, Voltip, Bobot, Tintic, Lumoth

Underground 5c
Primary Material	Rock 14
Secondary Material(s)	Rock 12 Plant Matter
Liquid	Water
Ore Distribution	Depth 3
Monster(s)	Small Aggressive Biped or Quadruped, Gleap, Lilodon, Miasmop, Skimbus, Pulpin

Underground 5d
Primary Material	Rock 15
Secondary Material(s)	Rock 17
Liquid	Water
Ore Distribution	Depth 3
Monster(s)	Small Aggressive Biped or Quadruped, Crabcano, Pyromantle, Fennix, Ignome, Crustoise
Special	Monsters in this layer are immune to Burning and Melting Status Effects

Core Layers

Garden Core Layer
Primary Material	Rock 19
Secondary Material(s)	Cobblestone
Liquid	Lava
Ore Distribution	Core
Monster(s)	None

Blaststone Core Layer
Primary Material	Blaststone
Secondary Material(s)	Rock 12 Rock 04
Liquid	Lava
Ore Distribution	Core
Monster(s)	None

Magmarock Core Layer
Primary Material	Magmarock
Secondary Material(s)	Rock 17 Rock 15
Liquid	Lava
Ore Distribution	Core
Monster(s)	None

Obsidian Core Layer
Primary Material	Obsidian
Secondary Material(s)	Rock 01 Rock 12
Liquid	Lava
Ore Distribution	Core
Monster(s)	None

Moon Core Layer
Primary Material	Moonrock
Secondary Material(s)	Dead Core
Liquid	None
Ore Distribution	None
Monster(s)	None
Special	Though classified as a secondary material, Dead Core is the only block that generates beneath a certain depth in this layer. This layer does not allow any Music Tracks to play.

Multi-Typed Layers

Underground 0a
Layer Types	Subsurface, Shallow Underground
Primary Material	Dirt
Secondary Material(s)	Clay Cobblestone
Liquid	Water
Ore Distribution	Depth 1
Monster(s)	Small Aggressive Biped or Quadruped, Gleap, Batong, Crustoise, Peblit, Bobfae

Underground 0b
Layer Types	Subsurface, Shallow Underground
Primary Material	Dirt
Secondary Material(s)	Sand Cobblestone Loose Silt
Liquid	Water
Ore Distribution	Depth 1
Monster(s)	Small Aggressive Biped or Quadruped, Paratail, Snaggler, Tintic, Peblit, Voltip, Spookit

Underground 1a
Layer Types	Subsurface, Shallow Underground
Primary Material	Clay
Secondary Material(s)	Cobblestone
Liquid	Water
Ore Distribution	Depth 1
Monster(s)	Small Aggressive Biped or Quadruped, Wisper

Underground 1b
Layer Types	Subsurface, Shallow Underground
Primary Material	Rock 19
Secondary Material(s)	Gravel Plant Matter
Liquid	Water
Ore Distribution	Depth 1
Monster(s)	Small Aggressive Biped or Quadruped, Iguarmor, Crutter, Snaunt, Bobfae, Batong, Peblit

Barren Underground
Layer Types	Subsurface, Shallow Underground, Mid Underground, Deep Underground, Core
Primary Material	Dry Sand
Secondary Material(s)	Dry Dirt Dire Stone Rock 15
Liquid	Water
Ore Distribution	None
Monster(s)	None
Special	This layer contains no caves of any kind.

Moon Underground
Layer Types	Subsurface, Shallow Underground, Mid Underground, Deep Underground
Primary Material	Moondust
Secondary Material(s)	Moonstone Moonrock
Liquid	Liquid Erchius Fuel
Ore Distribution	Moon
Monster(s)	None
Special	This layer does not allow any Music Tracks to play.

Layers Unique to The Ruin Mission

All layers in this category only allow Crystal Battle 1 (Loop) to play at all times of day.

Tentacle
Layer Types	Surface
Primary Material	Tentacle Cluster
Secondary Material(s)	Obsidian Jelly Blob
Liquid	Poison
Ore Distribution	None
Monster(s)	Tentacle Crawler, Tentacle Gnat, Tentacle Spawner, Tentacle Bomb, Tentacle Ghost, Tentacle Clam
Special	Monsters in this layer are immune to Poisoned Status Effect

Tentacle - Underground Tentacles
Layer Types	Subsurface, Shallow Underground
Primary Material	Tentacle Cluster
Secondary Material(s)	Obsidian Jelly Blob
Liquid	Poison
Ore Distribution	None
Monster(s)	Tentacle Crawler, Tentacle Gnat, Tentacle Spawner, Tentacle Bomb, Tentacle Ghost, Tentacle Clam

Tentacle - Underground Ceiling
Layer Types	Mid Underground
Primary Material	Tentacle Cluster
Secondary Material(s)	Obsidian Jelly Blob
Liquid	None
Ore Distribution	None
Monster(s)	Tentacle Crawler, Tentacle Gnat, Tentacle Spawner, Tentacle Bomb, Tentacle Ghost, Tentacle Clam
Special	An ocean of air begins 10 blocks below the center of this layer

Tentacle - Underground Floor
Layer Types	Deep Underground
Primary Material	Brains
Secondary Material(s)	Brains
Liquid	None
Ore Distribution	None
Monster(s)	None
Special	Contains one boss chamber enclosing the Heart of Ruin

Tentacle - Underground Core
Layer Types	Core
Primary Material	Brains
Secondary Material(s)	Brains
Liquid	None
Ore Distribution	None
Monster(s)	None
Special	This layer is completely filled with Brains