Plague

Plague is a debuff inflicted primarily by "plagued" enemies in the Jungle as well as weapons dropped by The Plaguebringer Goliath. It causes the target to lose 50 health per second and 4 defense as well as emitting large, green particles. When inflicted on a player, the player loses 10 health per second, 4 defense, and 15% movement speed. Additionally, vision is reduced similarly to the Darkness debuff, and the player emits large, green particles.

When the player has Alchemical Flask, Plaguebringer Carapace, Plague Hive, or Plague Reaper Vest equipped, they lose 5 health per second instead. Additionally, the Alchemical Flask and Plague Hive cancel out the vision loss effect too.

From player
In addition to the causes listed below, items that inflict Elemental Mix will inflict Plague as a part of that.

Trivia

 * The debuff's icon appears to depict a biohazard symbol (☣).
 * According to the lore for The Plaguebringer Goliath, the plague are infectious nano-machines.