You may have seen a bulbous structure lurking where berry-bearing Burgeoning Spiderwort plants had once grown. This is the Burgeoning Spiderwort mold. While its actual name is unknown, this fungus appears occasionally. It is destructable, so if you spot it, take a medium-large group of Pikmin to the area and have them attack it. Soon enough, the mold and its thread-like hyphae will slowly disappear, allowing the Burgeoning Spiderwort to grow once again. This is not harmful to your Pikmin, only to the plant.