Arnold is a minor character from the Pokémon episode "Hypno's Naptime." He's basically Ash's doppelgänger—same face and build, but with different clothes and hair color, which is honestly the only way you can tell them apart.
The episode centers on a group of kids, Arnold included, who get hypnotized by Hypno's sleep waves while at a local park. He ends up getting separated from everyone else in the chaos. Drowzee eventually saves the day by using its own dream waves to snap the hypnotized children awake, which gets Arnold back on his feet. By the episode's end, he reunites with his mother.
Content compiled by AnimeList.moe from publicly available sources.
