A Pink Agaricus has a spherical, pitch black head with two glowing yellow, beady eyes. It wears a round, pink cap on its head that sports two black, angular spirals on its front and several pale pink hearts decorating its top and sides. It also seems to wear an aquamarine smock that completely covers its legs and thin, fingerless arms. Its Heartless emblem is present on the front of this smock. The Pink Agaricus is by far the largest member of its family, standing twice as tall as Sora in Kingdom Hearts Final Mix.
The Pink Agaricus's name references its pink cap and the Agaricus genus of mushrooms.
When entering the Tree House in Deep Jungle or the Undersea Cave in Atlantica, three White Mushrooms will appear in various areas of the map. All of them perform the Stop charade, and once Sora has cast a Stop spell on all three, the Pink Agaricus will appear; in Deep Jungle, the Heartless shows up above the location where Sabor will have created a hole if Sora completed the optional battle with him, causing the Heartless to fall to the netting below.
The Pink Agaricus challenges Sora to strike it as many times as possible while it is Stopped. Sora can obtain the Heartless's unique synthesis material, Serenity Power, with as low as forty hits, but can only obtain its Prime Cap by inflicting the maximum of one hundred hits. For each hit, the Pink Agaricus will reward Sora with a progressively larger Tech Point bonus matching its ordinal, and for every ten, it will drop larger amounts of munny. However, any attacks landed by Donald and Goofy will detract from the final score.
In order to inflict the highest number of hits, the player should customize Donald and Goofy's AI to attack as little as possible, and customize Sora to maximize both his rate of attack, by using Aerora and Ragnarok, and the duration of Stop, by increasing his maximum MP. Sora will need a minimum of 14 MP to achieve 100 hits, but every additional MP will make it much easier to land the necessary attacks; Sora can acquire a maximum of 19 MP if he chose the Dream Rod at the Dive to the Heart, or 17 MP if he did not.
Sora should equip three of Atlas Armlet, Royal Crown, Cosmic Arts, or Shiva Belt, and either the Diamond Dust or Ultima Weapon; while the Ultima Weapon has one less MP and will cast a shorter Stop, its longer length means it can hit both the Heartless's head and its body, counting as two hits. Stop and Aerora should be set to Sora's shortcuts, and Ragnarok and Hurricane Blast should both be activated. If using the Ultima Weapon, all other aerial combat abilities should also be equipped.
Once the Pink Agaricus appears, Sora should target its head, cast Aerora on himself, and then cast Stop on the Heartless while leaping toward it, in order to inflict hits from Aerora while also removing the lag from Stop's casting; however, the player should make sure Sora only leaps close enough that Aerora touches the Heartless, as if he is too close, the player will not be able to leap high enough during Ragnarok to use Impact. As soon as he lands, he should use Ragnarok and activate its Impact at the moment of maximum power, for approximately 25 hits, then use aerial combos to attack the Heartless while waiting for Ragnarok to complete, as signified by its green aura fading. With all of the aerial combat abilities equipped, this will take one full combo and a few extra swings, and without them it will take two full combos. Once Ragnarok completes, the player should use it once more, repeating the process until Stop expires.
In the PlayStation 3 version of Kingdom Hearts HD 1.5 ReMIX, Ragnarok is activated by , which will also force Donald and Goofy to attack Sora's target regardless of their current AI settings. Therefore, they must be trapped somewhere where they cannot get to the Agaricus before Sora attacks it, which can only be accomplished in Deep Jungle. If Sabor did not break a hole in the floor, the best location for this is outside of the cabin, at the foot of the ladder to its roof. Once the Pink Agaricus has appeared, Sora should move to the ladder, then perform any summon to temporarily cause Donald and Goofy to disappear; Bambi is recommended, as he will replenish the MP Sora used casting Stop and the summon itself. Sora should then move into the cabin and position himself so that he can see Donald and Goofy's previous location, then dismiss Bambi—Donald and Goofy will reappear by the ladder, but will be unable to transport to Sora's side so long as they are still in his sight. As Ragnarok cannot be used during a summon, Sora must wait until Donald and Goofy's avatar and gauges reappear in the HUD before launching his assault on the Pink Agaricus. This was fixed for the release of Kingdom Hearts HD 1.5 + 2.5 ReMIX for the PlayStation 4, so that Donald and Goofy no longer attack the Pink Agaricus when you press .