Celadon Gym

In the anime
Celadon Gym appeared in Pokémon Scent-Sation!.

Ash wanted to challenge Erika to a gym battle, but the workers at the gym refused to allow his entry because he had earlier criticized a perfume shop, saying that all they do is turn men into zombies. They kicked him out of the shop for insulting them and when Ash found out that the gym is where the perfume was manufactured; he was visibly shocked.

With help from Team Rocket, Ash, in the guise of "Ashley," gained entry into the gym. However, Pikachu recognized that it was him, and ThunderShocked him to reveal Ash to everyone in the gym. After challenging Erika, she accepted his challenge, saying it's against Pokémon League rules to refuse a challenge.

Their battle was short-lived due to Team Rocket stealing the perfume. Several bombs soon detonated, setting the gym ablaze. However, thanks to the Pokémon of Ash, Misty and Brock, the gym survived. Erika gave Ash the Rainbow Badge for his help in not only saving the gym, but for protecting her Gloom as well.

In the Game
You must cut down trees.