Buff
Darkness
Darkness is a Terraria buff. 7 NPCs can inflict it: 
Blood Mummy, 
Blue Slime, 
Brain of Cthulhu and 4 more.
Description
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 per attempt to apply it. The game checks more conditions than shown here.