Evolve without an evolutionary stone

Miscellaneous glitches of Pokémon Red and Blue and Pokémon Yellow

Amazing Man (Red and Blue only) | Cable Club escape glitch | Celadon looping map trick | Champion Blue music muting glitch | Coastal Flooding | Confusion and Substitute glitch | Cooltrainer move | Cycling based glitch maps | Escape sprite handling glitch | Evolve without an evolutionary stone (Red and Blue only) | Evolving Raichu (Red and Blue only) | Expanded item pack | Expanded Pokédex | Focus Energy glitch | Get stuck in a wall | Ghost Bicycle glitch | Glitch encounter system | Glitch City RAM Manipulation | Infinite Blaine Door | Introduction Nidorino glitch (Red and Blue only) | Invisible PCs (Red and Blue only) | Invisible tree glitch | Item stack duplication glitch | Mute the music in the Pokémon League | Partial trapping move link battle glitch | Pokémon Tower Pokédex glitch | PP underflow glitches | Recovery move glitch | Rival's effect | See a Ghost without a Silph Scope | Selfdestruct and Substitute glitch | Silph Co. PC Glitch | Slot machine glitch | Stand on a tree | Statue behavior glitch (Red and Blue only) | Super effective move AI flaw (Red and Blue only) | Super Glitch | Surf down glitch | Swift miss glitch | Transform assumption glitch | Transform Empty Move Glitch | Trick Zone | Vending machine purchase glitch | Walk around with only fainted Pokémon (Red and Blue only) | Walking lag glitch | Walk on water through Surf | Walking Pikachu happiness glitch (Yellow only) | Wild appeared! | ZZAZZ Glitch

(view, talk, edit)

Requirements

1. A Pokemon that evolves by evolution stone, such as Clefairy, Staryu, Pikachu, etc, as the first Pokemon in your party.
2. One of the following Pokemon, each one of which corresponds to an evolution stone, in your party.

    •Exeggutor - Moon Stone 
    •HEX 20 Missingno. (no other Missingno will work. To get this you have to use the Ditto Trick with a Special of 32) - Fire Stone 
    •Psyduck - Leaf Stone 
    •Growlithe - Thunderstone
    •Onix - Water Stone 

Directions

1. Get into a trainer battle.

2. Have the first Pokemon in your party, the one your trying to evolve, gain a level.

3. Switch out the Pokemon your trying to evolve and put the Pokemon that corresponds to the necessary evolution stone.

4. Have that Pokemon finish the battle.

5. When the Battle is over then your Pokemon will evolve!

Additional Information

This glitch can also be done when encountering a wild Pokemon. Have the Pokemon your trying to evolve start the battle and then change Pokemon and place the Pokemon that corresponds to the required evolution stone in battle. Have the Pokemon end the battle. Both Pokemon will gain experience and for the glitch to work, the Pokemon your trying to evolve will need to gain a level from the experience it gains.

One should be precautious not to let this glitch happen to the starter pikachu on Pokemon Yellow because it will force it to evolve regardless of the fact that this is normally impossible as it refuses to take the thunderstone. However, one could always purposely evolve the pikachu to make either gameplay easier or fill in Raichu's pokedex entry but a Raichu with the player's OT will not follow the trainer.

Why It Works

The reason this glitch occurs is because the two operations, detecting a used a item and detecting which Pokemon is in battle, happen to share the same variable. The variable is 01XX91CF for Red and Blue, and 01XX90CF for Yellow. Use a Potion, and this variable is filled briefly by "14". Enter a battle, and send out a Pidgey, and the variable will become 24.

Video Demonstration

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