Goh's Dustox are the evolved form of
Goh's Cascoon. All three of his Cascoon evolved into Dustox after at the Sakuragi Institute bio-dome. They were spun up in a tree when all of Goh's Pokémon were fighting over food and it flooded the dome, endangering them from evolving but the Pokémon worked together to protect
Goh's Cascoon so they could evolve.