Astral Infection

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Not to be confused with Astral Injection, or the debuff of the same name.
The parabolic shape of the Astral Infection biome, as viewed on the map in a large world.
The meteor can be seen in pink at the top-center of the biome, with the Astral Beacon pillar positioned to the right of it.

This twisted dreamscape, surrounded by unnatural pillars under a dark and hazy sky.

The Astral Infection is a Hardmode biome added by the Calamity Mod. It crash-lands into the Dungeon side of the world via a meteor upon defeating the Wall of Flesh, which infects the nearby terrain and extends somewhat deep underground. The biome is filled with a sickly purple haze, and is populated by many alien creatures as well as dark monoliths of various sizes. It also contains a large Astral Monolith pillar, which houses an Astral Beacon on top of it. Players are alerted of the Astral Infection's arrival via a status message: "A star has fallen from the heavens!"

The meteor itself is made out of Astral Ore, which can only be mined after defeating the Astrum Deus boss. Tiles in a large area around and below the impact site are converted into Astral versions of themselves, including Astral Dirt, Astral Stone, Astral Sand, and Astral Ice, among others. Trees are converted into Astral Monoliths as well. However, the infection does not actively spread; only the initial impact converts tiles.

Two bosses, Astrum Aureus and Astrum Deus, can be summoned in this biome.


Astral Infection
CharactersUnique DropsMusic
Astral ProbeAstral Probe
Big SightseerBig Sightseer
Small SightseerSmall Sightseer

On Surface:

Astral SlimeAstral Slime


Hive (enemy)Hive
Stellar CulexStellar Culex


Fusion FeederFusion Feeder
Enchanted NightcrawlerEnchanted Nightcrawler


Astrum AureusAstrum Aureus
Astrum DeusAstrum Deus
From all enemies:

From Atlases:

Titan HeartTitan Heart

After defeating Astrum Aureus:

From Aries:
Stellar KnifeStellar Knife
From Astralachneas:
Astralachnea StaffAstralachnea Staff
From Astral Slimes:
Abandoned Slime StaffAbandoned Slime Staff
From Atlases:
Titan ArmTitan Arm
From Hadarians:
Hadarian WingsHadarian Wings
From Hives:
Hive PodHive Pod
From Mantises:
Astral ScytheAstral Scythe
From Novas:
Stellar CannonStellar Cannon
Glorious EndGlorious End
From Stellar Culexes:
Starbuster CoreStarbuster Core

From Astral Slimes
after defeating Astrum Deus:

Astral OreAstral Ore
From terrain:
Astral ClayAstral Clay
Astral DirtAstral Dirt
Astral IceAstral Ice
Astral OreAstral Ore
Astral MonolithAstral Monolith
Astral SandAstral Sand
Astral SandstoneAstral Sandstone
Astral SnowAstral Snow
Astral StoneAstral Stone
Celestial RemainsCelestial Remains
Hardened Astral SandHardened Astral Sand
Novae SlagNovae Slag
Astral BeaconAstral Beacon

From Fishing:

Aldebaran AlewifeAldebaran Alewife
Astral CrateAstral Crate
Twinkling PolloxTwinkling Pollox
Procyonid PrawnProcyonid Prawn
Arcturus AstroideanArcturus Astroidean
Gacruxian MolluskGacruxian Mollusk
Polaris ParrotfishPolaris Parrotfish
Ursa SergeantUrsa Sergeant
On Surface:
Music Box (Astral Biome)Music Box (Astral Biome)


Music Box (Underground Astral Biome)Music Box (Underground Astral Biome)


An Astral Infection meteor has a 100% chance of spawning after defeating the Wall of Flesh for the first time. After the first meteor has landed, defeating Astrum Aureus will always spawn a meteor in the world, assuming the limits have not been met yet.

No new meteors will fall if there are already a certain number of Astral Ore blocks above 0 depth. The limits are:

  • Small worlds: 200 Astral Ore blocks
  • Medium worlds: 400 Astral Ore blocks
  • Large worlds: 600 Astral Ore blocks

Alternatively, meteors will fall but not infect any nearby terrain if there are already a certain number of Astral-infected tiles in the world. Astral Ore blocks are not counted toward this total. The limits are:

  • Small worlds: 400 Astral-infected tiles
  • Medium worlds: 600 Astral-infected tiles
  • Large worlds: 800 Astral-infected tiles

16% of the world centered on the player's spawn point is protected from falling meteors. Meteors will not land within 25 tiles of a player, NPC, or a chest, nor directly on top of a platform.

Building a completed Skybridge across the entire world is not recommended pre-hardmode, as this will cause the Beacon to spawn on top of the skybridge, possibly out of reach. The biome will still spawn normally however.


Map Background Astral Infection.png
Astral Infection Bestiary and Map Background.
  • Player-created Astral biomes are possible by placing more than 950 Astral Dirt, Astral Stone, and/or Astral Ore in an area. Astral Grass that grows on Astral Dirt also counts toward this total.
  • Although meteorites will avoid hitting chests, one may still hit the edges of a Floating Island or a Planetoid.
  • Astral-infected blocks can be converted back to normal using Green Solution with a Clentaminator, however Purification Powder will also work. Conversely, blocks can be converted into their Astral Infection versions using Astral Solution.
  • Only the meteor's initial impact will infect nearby tiles. Despite its name, the infection will not spread on its own, unlike Evil Biomes or The Hallow.
  • Enemies specific to the Astral Infection require Astral blocks to spawn on; if the player is in the Astral Infection but the block the mob would spawn on isn't Astral, they are replaced by a universal enemy spawn.
    • In practice, this causes only ore slimes and Cosmic Elementals to spawn, which can be exploited to easily farm ores.


  • The Surface Astral Infection's theme is The Heaven-Sent Abomination, which was composed by the artist DM DOKURO.
    • This theme is a remake of the original theme that used to play in the biome: Heaven's Hell-Sent Gift.
    • If the Calamity Music add-on mod is disabled, the Space biome's theme will play for the whole Astral Infection instead.
  • The Underground Astral Infection's theme is Treasures Within the Abomination, which was also composed by the artist DM DOKURO.
  • The Astral Infection can infect several blocks that are unaffected by the Corruption, Crimson, or Hallow, including Dirt, Snow, Clay, Silt, and Desert Fossils.
  • The Enchanted Nightcrawlers which spawn naturally in this biome are clones of the original vanilla NPC, which drop the same item when caught with a Bug Net.
  • The Astral Infection used to be only a mini-biome known as the "Astral Meteor", which did not infect any tiles upon its crashing and possessed a different color scheme of yellow and pink.