Old man glitch

The Old Man glitch allows one to capture high-level or glitch Pokémon on the eastern Cinnabar Island strait. It is sometimes called the MissingNo. Glitch.

Requirements

A Red or Blue Version Pokémon game that has been played up to Cinnabar Island A Pokémon that knows Fly A Pokémon that knows Surf

Directions

1. Talk to the old man at Viridian City who shows you how to catch Pokémon. Say no to his question and watch his demonstration.

2. Fly to Cinnabar Island. Do not leave Viridian City before doing this.

3. Surf along the eastern coast of Cinnabar Island until you encounter a wild Poké .mon.

Additional Information

As you are Surfing, you should encounter Pokémon that you normally wouldn't see in the ocean, some of which are over Level 100. Eventually, you will encounter a Glitch Pokjmon called either 'M or MissingNo. Most chances you have heard of MissingNo. before; it is the most well-known Glitch Pok'mon and has been rumored to erase games, although it cannot.

MissingNo. and 'M are prized mainly because encountering one will give you 128 of the sixth item on your item list. This trick can therefore be used to give you infinite Master Balls, Rare Candies, etcetera, by using it again whenever your supply runs low.

Which other Pokémon you encounter with this glitch is determined by your name. To find out what Pok�mon will appear with your character's name, use our R/B Name Generator or the Big List.

How It Works

A technical description of this trick from PikaGlitchie's MissingNO. page (Zero_Six on the Forums): 1. When creating the map of which Pokémon appears where, the programmers made a mistake. The strip of land making up the Cinnibar Island Strait was programmed to be a place where wild Pokémon could appear, but they forgot to specify WHICH Pokémon could appear there! Whenever you enter a new area, the data for "What Pokémon appear where" is overwritten with the specific data for that area. However, because no data is specified for the Cinnibar Island Strait, the previous data will remain, abling you to evidentially catch Pokémon there from the last area you visited (this is what causes the (bulbapedia link to Safari Zone please) trick to take place).

2. When you watch the Old Man's demonstration, the picture and text change from your name to "Old Man". For this to happen, the programmers changed the variables given to your name so the picture and text can show up as "Old Man". These are stored in the byte containing the data for "What Pokémon appear where" as this was the place the programmers would be a safe place to store them until the demonstation finishes, and they would be overwritten when you entered a new place anyway, but when you go directly from the Old Man's demonstration to the Cinnibar Island Strait, the data won't be overwritten as it should, leaving your name's variables in the "What Pokémon appear where" byte. None of these variable's HEX Values make sense, so it would fit that the Pokémon encountered there would not make sense. The game brings up an empty HEX Value so Missingno appears.