From Bulbapedia, the community-driven Pokémon encyclopedia.
Timmy Grimm (Japanese: キミマロ Kimimaro) is a Pokémon Coordinator who appeared in the anime. He appeared in Disaster of Disguise and Disguise Da Limit.
Timmy was known as "The Phantom", because all of his Contest challenges were done in disguise. He dressed up as his Dusclops, and nobody knew his real name. This was due to the fact that his mother hated Pokémon, and forbade her son from battling with them. However, Timmy's father felt sorry for Timmy, so he would occasionally lie so Timmy could go out and participate in Contests.
When Mrs. Grimm found out Timmy's secret, she angrily drove off to the Contest Hall to confront him. But after seeing how close he was to his Pokémon, she began to encourage him to battle. As it turned out, Mrs. Grimm once loved Pokémon just as much as Timmy did. Her parents forbade her to use them, even taking the Poochyena she adopted far away, so she stopped caring about them to avoid getting hurt again. Timmy was able to remind her of the good times she had with her Pokémon and make her see that it's okay to like them.
Timmy competed in the Verdanturf Town Contest and battled against May and her Skitty. Timmy fought a great battle, but in the end, May was the winner of the Contest.
Timmy also had a cameo in Deceit and Assist, watching May at the Hoenn Grand Festival. He appears to know Chaz from All Things Bright and Beautifly! as he was seen watching the Grand Festival with him.
This listing is of Timmy's known Pokémon: