What happens if you catch all the Pokemon in Red?

If you catch all 151 Pokemon in Pokemon Red, you'll achieve a significant milestone in the game. However, there's no single, dramatic event that occurs upon completion. Here's what happens:

* No direct reward: Unlike some later games, there's no special item, character interaction, or fanfare when you catch the last Pokemon.

* The Pokedex is complete: You'll have a 100% complete Pokedex, giving you a sense of accomplishment.

* Access to the Elite Four: You'll be fully prepared to challenge the Elite Four and become the Pokemon League Champion.

* No further story progression: The game doesn't introduce new content or challenges after catching all Pokemon.

* Trading is possible: You can still trade with other players, though you won't be able to receive any new Pokemon that you haven't already caught.

Essentially, catching all Pokemon in Red is more about personal achievement than a game-altering event. It unlocks the final challenge, but the story ends with the defeat of the Elite Four.