1. A Pokemon with Fly/Teleport
2. The long-range trainer on Route 24
3. Your brain
1. Escape from the long-range trainer by a suitable method. Your Start button should be disabled.
2. Change boxes in a PC to save the game.
3. Reset the game. Your Start button should work again.
4. Do NOT fight any trainers in other maps.
5. Go back to Route 24. You'll notice that the long-range trainer ignore you unless you talk to him.
6. Talk to the trainer. This will start the battle.
7. Important: When the battle ends, there will be a message saying "With your ability, you could become a top leader in TEAM ROCKET!" Ending this message will make him spot you immediately, and the game will lock up. To avoid this, you must hold the direction that will take you away from his sight range, and then press Start immediately after the message ends. Then you can escape from him again and repeat this trick.
1. Doing this trick in other maps usually triggers the 0 ERROR glitch, since there are no events on those maps.
2. Workable maps: Mt. Moon B2F (unconfirmed), Route 24, Victory Road 2F (unconfirmed; I don't know if there's a long-range trainer), Route 16 (unconfirmed; I don't know if there's a long-range trainer), Route 12 (unconfirmed)