Fermented Spider Eye

The Fermented Spider Eye was first added in the 1.9 Pre-Release 2. It can be crafted from a spider eye, brown mushroom, and sugar on a crafting grid (unsorted). They cannot be eaten unlike the regular spider eye. They are used in a brewing stand to make Weakness potions. All potions made by Fermented Spider Eyes have negative effects.

Trivia

 * Fermented spider-eyes are used to make negative potions, which makes it useful for splash potions to use against enemies.