Relax, this isn't just your cartridge! It effects all Generation I games and is a well known glitch, it's called 0 Error.
0 Error is a glitch similar to the Mew glitch that causes Route 6 to become glitched.
>0 ERROR is a term used to refer to a glitch in Generation I of the Pokémon games. The glitch causes the entirety of Route 6 to be filled with glitched effects. It is named after the 0 ERROR box that may pop up if the player opens the menu in Route 6 while the glitch is active, or the game may just crash if the menu is opened.
Performing the glitch:
>Before performing the glitch, the player needs to make sure that the two Jr. Trainers and the Bug Catcher haven't been fought yet.
>The player must approach the Bug Catcher on Route 6 and pause the game when he notices the player, then use Fly or Teleport to return to Vermilion City, as if performing the Mew glitch. The player must walk east to Route 11 and battle any Trainer. The Trainer must walk towards the player. After defeating the Trainer, the player must return to Vermilion City and speak to any NPC besides the man with a Machop. The player must then return to Route 6. When the player enters Route 6, a message will appear, usually something that one of the Trainers on Route 6 says before they are battled, and a Trainer battle should start. After winning the battle, the "0 ERROR" glitch will be active. The game should not be saved while performing the 0 ERROR glitch.
The effects of the 0 ERROR glitch:
- The player and NPCs move very slowly.
- Random, glitchy noises can occur.
- The sprites of Trainers on the route will flicker and may teleport around.
- Player may be forced to battle Trainers continuously.
- Text may become glitched.
- The player may be unable to open the menu.
- Game freezes are likelier to occur.
If the game is saved after performing the glitch, the effects will become persistent.
(Skip to 1:37 if you just want to see the effects of the glitch.)