Pokémon Emerald Glitches

Walking on Water
You need to go to the Route 104 entrance to Marine Cave or the entrance to the Seafloor Cavern to perform this glitch. Stand facing the entrance, and keep mashing the B button when walking through the entrance. This will take several attempts, but if you time it just right you will be standing on the entrance, with the prompt asking you to re-surface. Select "yes" and you will be standing on a rock, and you can walk on the water! To end the glitch, you can dive back into the water and re-surface straight away. Alternatively, you can just fly to a town to end the glitch.