From Glitch City Laboratories
The Advanced Generation Glitched Pokémon Center is a glitch where someone tries to heal their Pokémon when they have none.
In Pokémon Red/Green/Blue/Yellow when the player attempted to heal at a PokéCenter with no Pokémon, glitch blocks would cover the screen corresponding to Pokéballs beyond the sixth slot and the game would either reset or became a Pokémon Center version of Glitch City. The same effect also occurs in Pokémon Ruby/Sapphire/Emerald/FireRed/Leafgreen, however instead of 255 Pokéballs appearing there will be 65535, instead of appearing as glitch blocks these use actual Poké Ball sprites and there would be no Glitch City like effect.
- Start a new game.
- Have a walk-through-walls code on.
- Walk to the Pokémon Center without getting a Pokémon or battling a Pokémon (without having the "Max Stats" code active.)
- Enter the PokéCenter and heal your Pokémon.
Fire Red/Leaf Green: