Dr. Namba appeare in Let's Save the Lugia! and was referred to as a Team Rocket Scientist in that chapter.
Hitmontop is a Pokémon belonging to him. He had a battle with Ash's Pikachu and dealt tons of damage to him. Hitmontop wearing the Rage Crown that made him stronger.
Hitmontop's only known move is Rolling Kick.
Gastly is another Pokémon belonging to Dr. Namba. None of Gastly's moves are known.