

The Contagion biome is a new biome added by the Avalon mod. It is a third alternative to the evil biomes, the Corruption and Crimson, and it is themed after illness. There are several unique drops to the Contagion, as well as new enemies, buffs, and mechanics.
Contents
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Blunderblight(Dropped with 100 Musket Balls)
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Nerve Numb Necklace
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Septic Cell
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Smogscreen
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Tetanus Chakram
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Burger
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Ring of Disgust(rare)
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Tentacle Spike
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Baccilite Ore
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Booger
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Bacterium Prime Mask
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Bacterium Prime Trophy(
10*1/10 (10%) chance) -
Treasure Bag(Dropped in Expert Mode, contains the Badge of Bacteria)
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Petri Dish(
25*1/4 (25%) chance in Master Mode) -
Bacterium Prime Relic(Dropped in Master Mode)
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Contagion Key(1/2500 chance)
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Blindfold
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Dark Shard
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Megaphone
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Mummy set(rare)
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Virulent Mushroom
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Barfbush
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Barfbush Seeds(during Full Moon or Blood Moon)
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Coughwood(from trees)
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Ickfish
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Sickly Trout
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Anchor Whipworm(Hardmode only)
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Contagion Crate(Pre-Hardmode only)
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Plague Crate(Hardmode only)
Spread
The Contagion spreads itself, similar to the Corruption, the Crimson and the Hallow. This means that it slowly converts certain susceptible tiles that are in the vicinity of existing Contagion blocks. While its spreading capabilities are very limited during pre-Hardmode, it spreads much faster and more aggressively after defeating the Wall of Flesh. Defeating Plantera for the first time reduces the speed of the Contagion's spread by 1/2 (50%).
Contagion Desert
In Hardmode, Contagion spreads through Deserts, transforming them into Contagion Deserts. A Contagion Desert is fairly similar to a regular Contagion biome: The theme music and enemies are the same, with the addition of:
- Surface Desert:
- Underground Desert:
- During a Sandstorm:
Sand is replaced by Snotsand. Cacti drop ordinary cactus when cut, even though they have a different color. Waterleaf is unable to grow in Contagion Deserts.
Contagion Snow
Like the Contagion Desert, Contagion Snow biomes are created when Contagion spreads into a Snow biome during Hardmode. Snow Block is not convertible, but Ice Block can be converted into Yellow Ice Block. Yellow Ice can be created during generation if a Contagion biome overlaps a Snow biome, but it will not spread until Hardmode.
Notes


- During the generation process of a world with the Contagion, the left half of the progress bar frame will be green, and the main progress bar will be lavender.
- Contagion can be created or spread artificially using Contagion Seeds, Vomit Water, and either the Clentaminator or the Terraformer with Contagion Solution, obtainable from the Steampunker during a Blood Moon in Contagion worlds (she sells Purple Solution and Red Solution in Corrupt and Crimson worlds instead).
- It is possible to create an artificial Contagion biome in a Corrupt or Crimson world without the use of another world. To do so, one must buy Contagion Seeds in Hardmode from the Dryad while in a Graveyard.
- Artificially creating a new Contagion biome requires at least 300 Contagion tiles. Although Corruption or Crimson might replace Contagion at world generation, it does not prevent Contagion from being artificially created in a Corruption or Crimson world (and vice versa), nor does it prevent the Contagion biome's spread.
- During Hardmode, any enemy in the Contagion or Underground Contagion has a
0.04*1/2500 (0.04%) chance to drop a Contagion Key.
Trivia
- The music used in the Contagion was created by Turquoise.
History
- 1.2.3:
- Color of the sky in the Contagion is now more green.
- Can no longer receive Corruption/Crimson fishing quests in a Contagion world.
- No longer gets too dark during night, causing lighting issues.
- Tall Grass now properly generates all variants upon world creation.
- Virulent Mushrooms now generate upon world creation.
- Added a new background variant.
- 1.2.1:
- Reduced chance for Contagion Thorny Bushes to grow.
- Contagion now only requires 300 tiles to count as the biome, instead of 351.
- Music no longer cuts out when there are more than 75 contagion tiles nearby.
- 1.2:
- Coughwood trees now drop the proper items when shaken.
- Coughwood trees no longer drop Forest tree loot when shaken.
- Contagion now only requires 300 tiles to count as the biome, instead of 351.
- Music no longer cuts out when there are more than 75 contagion tiles nearby.
- Coughwood trees now drop the proper items when shaken.
- 1.1.3: Contagion world icon overlay for worlds on "The Constant" seed now fully covers the crimson leaves.
- 1.0.0: Introduced.