Key to the Fungus Dungeon

 is a key.

Obtaining

 * Dropped by
 * Mush Rhume
 * Mush Mish
 * Mush Tup
 * Mushmunch
 * Mushnid
 * Trumperelle
 * Crafted by a Handyman (Lv. 100) from

Uses

 * Access
 * Fungus Dungeon