Pokemon Season 1 Episode 63 - The Battle of the Badge

⁣In Viridian City, Ash goes to the Gym, but Gary gets in there before him
and gets beaten by a never before seen Pokémon (Mewtwo), which the
PokéDex cannot identify. Luckily, Giovanni leaves the Gym and puts
Jessie and James in charge. Then, Ash challenges them. However, after
losing three of Giovanni's Pokémon, Jessie and James use their own.
Then, Ash sends them blasting off, and wins the badge.