Foster is a minor character from Pokémon: Johto League Champions.
Season 4: Johto League Champions
Foster, whose mentor had been Prof. Oak, first appeared in the episode Fossil Fools and was a researcher in Pokémon fossils. Foster wanted to build a park based on Fossil Pokémon. He showed Oak, Ash, Misty and Brock an Omastar and some Omanyte that came. However, many more came and due to the reports of lack of water, he and his friends headed to the mountain, to see Team Rocket draining the lake. Team Rocket were defeated and the fossil Pokémon came back to live in the lake. He has not appeared since.