Pokémon : S3 | E10 – The Chikorita Rescue

On their way to Violet City, Ash and his friends have decided to take a mountainous trail, though Brock complains about how cold it is. Just then, he notices a wild Chikorita. Remembering Casey and her Chikorita, Ash loudly proclaims his intent to catch the Chikorita, which surprisingly doesn't scare her away. Ash promptly sends out Bulbasaur. Chikorita charges, but Bulbasaur counters with Vine Whip. Chikorita then uses Razor Leaf, but Bulbasaur shoots them down with its own Razor Leaf flurry, then Tackles Chikorita. Ash throws his Poké Ball, but Chikorita simply swats it back, then catches Bulbasaur off-guard with a Vine Whip to the head.

Ash recalls Bulbasaur and sends out Charizard, though Chikorita remains steadfast. She charges at Charizard, who simply holds her off with his foot. Ash orders a Flamethrower, but Chikorita uses Vine Whip to trip Charizard, who inadvertently burns Ash. Chikorita then fires another Razor Leaf flurry, but Charizard burns the leaves with Flamethrower, then flies in for a Tackle. Chikorita counters with another Vine Whip to the head, but this time, her vines get caught by Charizard's arms, causing both Pokémon to crash into a nearby mountain. Everyone runs over, and Ash recalls Charizard. Chikorita struggles to stand and collapses again from exhaustion. The group decides to take her to the nearest Pokémon Center. Not far away, Team Rocket watches the fight, with Jessie left very impressed by how strong Chikorita was, and believing that they need that kind of toughness on Team Rocket. However, Meowth is offended by her reasoning to capture Chikorita.
(Source: Bulbapedia)