A host-parasite pair in which the parasite mushroom has taken over the host bug. Prefers damp places.
The bug host is drained of energy by the mushrooms on its back. They appear to do all the thinking.
It stays mostly in dark, damp places, the preference not of the bug, but of the big mush rooms on its back.
The larger the mushroom on its back grows, the stronger the mush room spores it scatters.
When nothing's left to extract from the bug, the mushrooms on its back leave spores on the bug's egg.
— Pokédex entries (via PokeAPI)