Mike

Matt is a character of the day who appeared in Pinch Healing. He is a Pokésitter and the final character of the day to appear in Pokémon the Series: Ruby and Sapphire.

Matt was transporting Pokémon by bus when an Electrode fell on it and caused him to have an accident. He called the local Pokémon Center where the Nurse Joy in charge happened to be sick. Ash, his friends and Scott came by to tow the bus. They were about to leave when, all of a sudden, a Bagon that Matt was looking after got lost after chasing a Butterfree.

With the help of Ash, he was able to get Bagon back. However, after the ordeal, Bagon fainted in Matt's arms and that was when he discovered it had a terrible fever. They rushed it to the Pokémon Center as quick as possible. There, Matt couldn't help but feel guilty about Bagon. He felt he had a responsibility to care of the Pokémon Trainers had left with him. During this time, two people came into the Pokémon Center, claiming to be workers from the Pokémon Day Care center that Matt worked at. They gathered up all of the Pokémon and put them in a box. Matt did not believe their claims, however, and confronted them about it, but then, a smokescreen was spewed from the box. The impostors took off and revealed themselves as Team Rocket.

As they were escaping in their balloon, Ash almost commanded Pikachu to use Thunderbolt but stopped when he realized that it would also hurt the Pokémon Team Rocket stole. May remembered that the Larvitar they stole has a powerful Sandstorm attack and asked it to use it. It did so and Team Rocket's balloon crashed as a result. Ash took care of it from there and Team Rocket is defeated. They were approached by Brock, who informed Matt that Bagon's fever had broken, relieving him. The next day, Scott managed to repair Matt's bus and he was able to return the Pokémon back to their Trainers.

(Source: Bulbapedia)