* Rage Candy Bar Salesman: This is a character who appears in Pokemon FireRed and LeafGreen. He's outside the Pokemon League and only appears if you've beaten the Elite Four but haven't caught a Red Gyarados.
* Red Gyarados: This rare, powerful Gyarados is found in the Lake of Rage in the same games.
Here's how you get past the Rage Candy Bar Salesman:
1. Catch the Red Gyarados: You need to capture the Red Gyarados in the Lake of Rage.
2. Talk to the Salesman: Once you have the Red Gyarados, go back to the Pokemon League and talk to the Salesman. He will recognize your Red Gyarados and let you pass.
Why does he block you?
The Salesman is actually Team Rocket in disguise. They want to use the Red Gyarados' immense power to take over the world, and they won't let anyone pass until they get their hands on it.
Let me know if you have any other questions about Pokemon!