#3 "Ash Catches A Pokémon"

    He catches two, in fact. Ash and Pikachu - with Misty tagging along, swearing revenge for the bike - travel through Viridian Forest. First, he gets a Caterpie without weakening it first. Misty does not appreciate this, as she is terrified of bugs (typical girl...). A little later, Ash shows his brilliant strategy by sending Caterpie against a wild Pidgeotto (fortunately he ends up with Pikachu fighting) and captures it too.

    Then Team Rocket appears, looking for revenge because Ash beat them at Viridian. Also, they are impressed with Pikachu. Ash manages to beat them with Caterpie's string shot, and Caterpie evolves into Metapod.