The Boomba Mushroom is a harvestable that can be found in the Frontier. It can be found from various sources and locations throughout the Frontier including but not limited to:
- A possible reward from a Treasure Chest.
- A possible reward from the Firefly Quest.
- A possible reward from the Otherworld Tower.
- A rare drop from the Ancient Iron Knight.
- Being harvested from Ancient Forest, Celestial Peak, Farm Fortress, Great Pine Forest, Greenhorn Grove, Inside, Matumada, Rubble Spring, The Deep Forest, The Forgotten Lands, The Maze Wood, The Pits, Topple Hill, and Topple Town.
In appearance, the Boomba Mushroom is a beige-blue mushroom possessing a blue cap with red speckles. Its stem has an orangeish-beige hue applied to it. Players can exchange 3 Boomba Mushrooms for 25,000 gold during the Slayer's Tasks. If the player has no purpose for the Boomba Mushroom, it can be sold for 3,000 gold.
- A cluster of Boomba Mushrooms can be seen contained in a bin on a bookshelf in Slayer's building, located in Topple Town.
- Its name originates from its explosive properties. The word Boomba contains an onomatopoeia, 'boom', referencing the sound of an explosion.
- The Boomba Mushroom can be seen in some of the magical boxes located in the library-room of The Mansion.