From the Super Mario Wiki
Shrooms are found in Fungi Forest during the day. Similar to the attack of Klobbers, they will wait in the ground, looking like normal mushrooms. If a Kong approaches it, the Shroom jumps out at them and attack. When they attack, the Shroom chases the Kong through the forest, and the Kong can take some damage if touched by it. Shroom are fairly weak enemies and a few attacks can defeat one. A Shroom can be defeated also from afar by blasting it with a weapon or an Orange.
At night in Fungi Forest, Shroom are replaced by the club-wielding Koshas.
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