Poison Rune

The Poison Rune is an item used primarily as ammunition for staves.

Rune Shrine
Using Unpowered Runes or Charged Runes on a Rune Shrine that is centered on a Poison Rune Shrine, will convert those Runes into Poison Runes. The player can only convert Runes into Poison Runes if their Runation level is 22 or higher.

Mob Drops
Poison Runes can be obtained as a drop from the following mobs:
 * Green Guardian
 * King Shroomus
 * Voxxulon

Rune Box
Poison Runes can be found when opening a Rune Box.

Rune Randomizer
Using Unpowered Runes or Charged Runes on a Rune Randomizer has a chance to convert them into Poison Runes.

Ammunition
Poison Runes are required as ammunition for the following Staves: Additionally, Runic Sword can consume Poison Runes when attacking to poison mobs on hit.
 * Nightmare Staff
 * Noxious Staff
 * Poison Staff
 * Tangle Staff

Banner Pattern
Crafting a Poison Rune with a vanilla Banner and a dye will give the Banner a pattern that resembles the Poison Rune's symbol.

Rune Templar
Using a Poison Rune and Runic Energy on a green Rune Templar will activate it. This will not consume the Poison Rune, only the Runic Energy.