You feel lightheaded after just touching this. Ingesting it would be dangerous.
— In-game Description

The Rare Mushroom is an ingredient that can be used in several Recipes produced in the Cooking Pot or Industrial Cooker, including Shadow Steak Saute and Mindwipe Tonic, and in the production of Re-Fertilizer. The Rare Mushroom is harvested from mining Crystal and trees in the swamps with any berry gatherer herbivore, preferably the Ankylosaurus.