Mushrooms are near-white glowing versions of the real world fungus. They are quite rare fungi compared to other flora in rain world, but generally grow together in clusters of 2-3. They are edible, but don't count as food for hibernation. Mushrooms can be found in any region except Five Pebbles and Shoreline.
When consumed, they activate a slow-motion effect for about 20 seconds of real time. This also gives slugcat the ability to jump higher and move slightly faster.