Sebastian is a butler of James' family at the mansion in Sinnoh.
Sebastian is the butler loyal to James and his family. When James arrived to the mansion, Sebastian gave him, Jessie and Meowth food, but they had to go as soon as James heard Jessibelle would come to marry him. Later, when Ash found a chest, Team Rocket came to get the chest. Growlie recognizes James and undisguised him, so the butler called to Jessibelle James arrived. He and Jessibelle ran to get James back, in which they almost succeeded, though James ran away from them.
Spinarak is a Pokémon owned by Sebastian. It was to capture James using String Shot, but it and Sebastian were confused via Mime Jr.'s Teeter Dance.