From Bulbapedia, the community-driven Pokémon encyclopedia.
Raymond (Japanese: レイモンド Raymond) is a Pokémon Trainer Ash battled in Mewtwo Strikes Back. His Japanese voice actor is Raymond Johnson.
While Ash and his friends were waiting to eat, he approached them and asked Ash for a battle. Although he claimed he was too weak to work, Ash immediately jumped up, ready for battle.
However, despite Raymond's eagerness, Ash successfully knocked out all five of his Pokémon in rapid succession. In fact, Pikachu took out three of the Trainer's Pokémon in one Thundershock. The trainer was stunned by the defeat, and has not been seen since his brief appearance.
Notably, Raymond had an as-yet-unknown Generation II Pokémon when he appeared, a Donphan.