Chapter 250 - 250: Energy Crystal
Dustox is a Bug and Poison-type Pokémon, doubly vulnerable to Flying, Rock, Fire, and Psychic-type moves.
Slowpoke and Murkrow can serve as the main Pokémon to attack.
Sneasel and Haunter can assist offensively by restraining the enemies.
As for Skorupi, the level of the Pokémon here is too high for it, so it's not very suitable for it to participate in the battle.
And Miltank isn't quite up to the team's level, so this is a good opportunity to train it a bit more.
...
The next day.
On an unnamed island.
Cain led his Pokémon into Dustox territory.
The Dustox aren't as easy to handle as Beautifly; Cain was attacked as soon as he entered.
Additionally, the Dustox forest is filled with fine dust everywhere. If you accidentally inhale too much, you can become paralyzed, poisoned, or fall asleep.