The Underground Corruption is a biome. It is the underground version of the surface-level Corruption. Prior to Hardmode, it will only naturally exist in the lowest parts of Chasms, and only if they are deep enough to reach the Cavern layer. Regardless, once the Wall of Flesh is defeated, more Underground Corruption will be created at and below the cavern layer. It operates similarly to surface Corruption, being composed of Ebonstone and Ebonsand, though it spawns different enemies in Hardmode.
Underground Corruption spreads just like surface Corruption, and similarly can not spread through Hallow.
Small pockets of Underground Corruption can be created through the breaking of Demon Altars, which can convert a single random Stone Block in the world into Ebonstone upon its destruction.
Underground Corruption does not suppress the spawn of other underground and cavern enemies. During Hardmode, all enemies killed in the Underground Corruption have a
20*1/5 (20%) chance to drop a Soul of Night. In Expert Mode, this chance increases to a 36*9/25 (36%) chance.
Note: Most characteristics of surface Corruption also apply to the Underground Corruption. See The Corruption.
This content is transcluded from Biome backgrounds § Underground Corruption.
On the Desktop version, Console version, and Mobile version, the following backgrounds are used. On the Old-gen console version and Nintendo version, the cavern layer background for any other biome the player is in is dynamically tinted purple.
- Desktop 18.104.22.168: Added Otherworldly Underground Corruption track from the cancelled Terraria: Otherworld.
- Desktop 22.214.171.124: Corruption chasms that extend into the underground layer are now classified as the Underground Corruption, complete with music. Unique enemies will not spawn pre-hardmode.
- Desktop 1.2.3: Added biome specific stalactite variations.
- Desktop 1.1: Introduced.
- Console-Release: Introduced.
- Switch 1.0.711.6: Introduced.
- Mobile-Release: Introduced.
- 3DS-Release: Introduced.