There are four types of Mushroom Heartless in KINGDOM HEARTS Final Mix, and each one has its own set of rare rewards for defeating it, including the rare and valuable Mystery Goo!

White Mushroom

White Mushrooms are the most common form of Mushroom Heartless, and are by far the easiest to get a plethora of prizes out of. Unfortunately, they are not all that easy to find. They only respond to magical attacks, but you need to be careful. White Mushrooms only reward those who use the right magic spells to defeat them. There are a series of actions that a White Mushroom will perform, and each action corresponds to a specific spell. They are as follows:

Shivers: Fire Magic
Fans self: Blizzard Magic
Light appears overhead: Thunder Magic
Falls: Cure Magic
Hovers: Gravity Magic
Freezes in place: Stop Magic
Spins in place: Aero Magic

The trick to appeasing a White Mushroom is to use the correct spell when it performs the corresponding action. Perform three correct spells and the White Mushroom will drop its prizes and leave. There are eight specific prizes that are worth getting from a White Mushroom – one is the Mystery Goo, of course, and the others are the seven Spell Arts. The Spell Arts are items dropped by a White Mushroom who has been defeated by the same spell three times in a row. For example, if a White Mushroom performs shivers three times in a row, and you cast Fire Magic three times in a row to defeat it, the White Mushroom will reward you with a Fire Arts. There is one Spell Arts for each of the seven types of Magic. If you collect them all, you can bring them to Merlin in Traverse Town and he will reward you with the Dream Shield for Goofy.

White Mushrooms don’t appear often, but when they do, it will always be in one of the following locations.  The actions they perform vary depending on the world you find them in.

Traverse Town: Red Room (Fire, Blizzard, Thunder)
Wonderland: Lotus Forest (Fire, Blizzard, Thunder)
Deep Jungle: Camp (Fire, Blizzard, Thunder, Cure)
Deep Jungle: Treehouse (Stop – Summons Pink Agaricus)
Agrabah: Treasure Room (Fire, Blizzard, Thunder, Gravity)
Halloween Town: Graveyard (Fire, Blizzard, Thunder, Aero)
Atlantica: Below Deck (Fire, Blizzard, Thunder, Stop)
Atlantica: Undersea Cave (Stop – Summons Pink Agaricus)
End of the World: Linked Worlds (All Magic)

Black Fungus

The Black Fungus is arguably the hardest of the three Mushroom Heartless to get any rewards out of, not because they are hard to beat, but simply because their item drop-rate is so low. The best way to get a Black Fungus to drop items is to defeat it with the finishing blow of a combo with a critical hit with Lucky Strike equipped, which is pretty hard to do. The benefit to hunting down these Mushroom Heartless versus any other kind is that the Black Fungus is the only one who will drop the rare Mystery Mold in addition to the Mystery Goo. Mystery Mold is a valuable item that sells for 9,999 Munny! The Black Fungus can be found in the following locations:

Agrabah: Bazaar
Halloween Town: Moonlight Hill
Hollow Bastion: Cell
End of the World: Linked Worlds

Rare Truffle

The last of the three Mushroom Heartless is the Rare Truffle. Its prizes are difficult to obtain, but they are arguably the best source of Mystery Goo in the entire game! Of course, there’s a catch – you have to keep them up in the air, racking up as many consecutive hits as you can. The more hits you get before you drop the Rare Truffle, the more prizes it drops. There are three benchmarks to aim for: 10, 50, and 100. At each of these increments, the Rare Truffle will drop a group of prizes. Obviously, it takes more consecutive hits to collect the more rare and valuable prizes. The best location to exploit a Rare Truffle for all it has to offer is in Neverland on the Ship’s Deck. With the ability to fly, it’s a lot easier to stay under the Rare Truffle and reach 100 hits to get every prize available. Two noteworthy prizes to watch for are the Shiitake Rank and the Matsutake Rank, rare items that you can sell for 100 Munny and 500 Munny apiece (respectively). The locations for Rare Truffles are as follows:

Monstro: Throat
Halloween Town: Bridge
Neverland: Ship’s Deck
End of the World: Linked Worlds

Pink Agaricus

The Pink Agaricus is a unique Heartless exclusive to KINGDOM HEARTS Final Mix, and will not appear normally unless summoned under the correct criteria.  If you ever enter the Tree House in Deep Jungle or the Undersea Cave in Atlantica and find three White Mushrooms all frozen still, it is possible to summon the Pink Agaricus.  Casting Stop magic on all three White Mushrooms will cause the Pink Agaricus to spawn, and from there, the real encounter begins.

Cast Stopga on the Pink Agaricus and then immediately proceed to land as many hits as possible before the effects of Stopga wear off.  The Pink Agaricus awards 1 point for each hit you land, and its prize drops are dependent on the score you earn.  The Pink Agaricus is the only source of Serenity Powers in the entire game, and also the only way to acquire the Premium Cap accessory.

The best way to rack up as many hits as possible is to encounter it in the Tree House in Deep Jungle and attack it with Ragnarok while you have Aeroga cast on Sora.  The Pink Agaricus drops the following prizes depending on how many hits you were able to land:

0-9 HitsNo prizes
10-39 Hits: Potion (100%)
40-69 Hits: Hi-Potion (100%), Serenity Power (10%)
70-99 Hits: Ether (100%), Serenity Power (20%)
100 Hits: Serenity Power (100%), Premium Cap (100%)