Water-shroom

Water-shrooms (ミズキノコ) are most commonly found growing on Shroombears in the western side of the Goblet of Giants. Whether they grow on other creatures is unknown.

Description
When raw Water-shrooms are attached to a living creature, they suck out the nutrients of the host and store it. When the host is close to death, the nutrients stored in the caps of the shrooms are released back into the host's body, letting both the host and the shrooms stay alive.

They were an essential part of Riko's healing process after she was attacked by the Orb Piercer. The fungi were transplanted from a Shroombear onto Riko's arm and released their nutrients into her wound, allowing her to heal more quickly. They are extremely painful to remove.