From Glitch City Laboratories
The Land on a Rock in the Sky Pillar Glitch refers to a very minor glitch in Pokémon Ruby, Pokémon Sapphire and Pokémon Emerald which involves the player being able to land on a rock after falling through a crack in the ground. Through normal gameplay, the player is usually unable to stand on top of a rock.
- The player needs a Mach Bike so that he or she can make it to the second floor of Sky Pillar.
- In order to access Sky Pillar, the player needs to have already beaten the Pokémon League.
- Access the second floor or Sky Pillar, where Rayquaza can usually be caught.
- On the fourth crumbling area (the first one to the right hand side) if the player stays all the way to the right hand side (right next to the wall) and falls through the last hole there he or she will land on a rock.
-  - A list of minor glitches on pokeglitch.tripod.com, including "Land on a Rock in Sky Pillar."