Pokemon - episode 74 - 25 Nov, 1998

While training, Ash and his friends accidentally uncover the ruins of Pokémopolis (ポケモニア, Pokemonia), an ancient city. A giant Gengar and a giant Alakazam who were respectively trapped inside a "dark device" and a strange urn are awakened. The two start to fight one another when a giant Jigglypuff appears and puts them to sleep. (Source: Wikipedia)