Buff
Darkness
Darkness is a Terraria buff. 7 NPCs can inflict it: 
Blood Mummy, 
Blue Slime, 
Brain of Cthulhu and 4 more.
What it does
Decreased light vision
Type
- Debuff: it harms you.
- It is not saved when you leave the world.
Inflicted by
| Source | Chance | Duration | Conditions |
|---|---|---|---|
| Blood Mummy | 1 in 4 (25%) | 15 seconds | |
| Blue Slime | 1 in 4 (25%) | 15 seconds | more conditions apply |
| Brain of Cthulhu | 11/243 (4.53%) | In Expert or Master Mode | |
 Corrupt Slime | 1 in 4 (25%) | 15 seconds | |
 Creeper | 11/81 (13.6%) | In Expert or Master Mode | |
 Crimslime | 1 in 4 (25%) | 15 seconds | |
 Dark Mummy | 1 in 4 (25%) | 15 seconds | |
| Demon Sickle (projectile) | 1 in 3 (33.3%) | 15 seconds | Unless the player has Journey godmode on |
Chance is for each time the game tries to apply it. Duration is the time the game code sets. “More conditions apply” means the game checks more than this table shows.