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 right above it.

Bestiary Astral Surface.png "This twisted dreamscape is a starborne equivalent of the mundane rot you see in your lands." Bestiary Astral Underground.png

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 sound and 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
Sightseer SpitterSightseer Spitter
Sightseer ColliderSightseer Collider

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 Infection)Music Box (Astral Infection)


Music Box (Underground Astral Infection)Music Box (Underground Astral Infection)


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.
    • Astral Ice biomes require at least 951 Astral Ice .
    • Astral Desert biomes require at least 951 Astral Sand, Hardened Astral Sand, and/or Astral Sandstone.
  • 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, and likewise with Purification Powder. 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.



These history sections are still a work-in-progress, and may not yet contain changes relevant to the current version of the Calamity Mod.
    • No longer lands very close to the edge of the world.
    • Adjusted background layering and parallax.
    • Changed fog and skylight effects. It now renders with stars.
    • Fixed it converting safe Living Wood Walls instead of unsafe, naturally generated ones.
    • Added proper rain color.
    • Generation was improved. The meteor is no longer blocked by platforms spanning over the world.
      • Improved the Astral Monolith Pillar so that it doesn't generate in the air.
      • Changed the Astral biome's X coordinate limit a bit so it can't spawn too close to the Dungeon.
    • Added biome spawning sound.
    • Enchanted Nightcrawlers can now spawn from ambient objects and wild grass.
    • Now requires 951 or more tiles for every biome variant, instead of 301 or more for the Astral Snow specifically.
    • Now converts Copper Ore, Gold Ore, Iron Ore, Lead Ore, Platinum Ore, Silver Ore, Tin Ore, and Tungsten Ore into Astral Ore.
    • Now spawns an Astral Beacon structure.
    • Fixed Twinklers not spawning from Firefly Statues in the biome.
  • Now avoids the Sulphurous Sea completely.
    • The player now has decreased gravity in Death Mode.
    • Increased the intensity of the sky effect by 75% in Death Mode.
    • Can now convert Living Wood and Living Wood Wall into Astral Monolith and Astral Monolith Wall. Living Leaf are destroyed upon converting.
  • Can now convert Slush Blocks to Novae Slag.
    • Added Enchanted Nightcrawler.
    • Resprited underground and caverns backgrounds.
  • Now only strikes on the Dungeon side of the world.
    • Slowed down the theme.
    • Lowered Astral Meteor impact zone.
    • Astral Meteor reworked:
      • Original meteor spawned by defeating Wall of Flesh now converts a large amount of blocks near it into new, Astral variants.
      • Moved Astral Meteor strike zone lower in the world.
      • Slightly increased general enemy spawn rates.
  • Fixed its music playing even while music volume was set to zero.
  • Reduced Wall of Flesh's chance to drop another Astral Meteor from 10% to 5%.