The Battle of the Badge (Japanese: トキワジム!さいごのバッジ!Tokiwa Gym! The Last Badge!) is episode 63 of the Pokémon anime. It was first broadcast in Japan on September 17, 1998 and in the United States on September 25, 1999.
Spoiler warning: this article may contain major plot or ending details.
Some scenes of this episode are similar to scenes from the first movie. These include the battle with Giovanni and Gary.
This marks the first and only time a Gym Leader refuses to give the badge to Ash despite winning the battle fair and square.
It's subtly hinted that Mewtwo's Armor might have been interfering with the Pokédex's scanning ability. When the Pokédex was saying that the Pokémon was unknown and didn't have any available data, there was static interference on the Pokédex screen as well, which none of the other unidentified pokémon both prior and after had.