Trainer mutation glitch

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Revision as of 21:56, 21 January 2017 by >Torchickens (→‎Technical details: Convert to table)

Trainer mutation glitch is a closed menu Select glitch in Pokémon Red, Green, and Pokémon Blue (Japanese).

Please note that this glitch only exists in the Japanese versions of the game, or is otherwise a glitch
from a Pokémon game which was only released in Japan.

It allows the player to change what groups of Trainers in a map say, how they turn, and what class they are. If the new 'class' is less than 200 (C8), then they will turn into Pokémon. The player can also change the Pokémon's levels.

Unfortunately the player can't manipulate the species/class of the first Trainer IDs 1-4 in a map unless they have a Pokémon with specific stat experiences (so no 'fresh' Pokémon) but they should be able to manipulate others.

Basic steps

1) Press Select on the 20th item.

2) Exit and go into battle, then swap the 20th Pokémon with a Pokémon of your choice.

3) Without using a warp, go to a Trainer and they should have 'mutated'. Do note that a Trainer's text may freeze the game, and beware of Missingno. in Red/Green.

The game may freeze after the switch with no documented fix.

Technical details

Every Trainer on a map has an ID. This glitch lets you change the Pokémon (or Trainer) and level that a certain Trainer ID is. The ID can be tracked with memory viewer by talking to a Trainer and viewing address CC55, CD4F, or CF0E. As maps have multiple Trainers (and IDs), you can mutate more than one Trainer.

When you switch the Pokémon, you're actually switching the 20th Pokémon with the first. This puts various Pokémon data into unrelated data, and one group causes the Trainer mutation effects.

Original Address Original Address 1 data Destination Address Destination Address data
N/A N/A D463 Trainer 01 turning data
N/A N/A D464 Trainer 01 text
N/A N/A D465 Trainer 02 turning data
N/A N/A D466 Trainer 02 text
N/A N/A D467 Trainer 03 turning data
N/A N/A D468 Trainer 03 text
N/A N/A D469 Trainer 04 turning data
N/A N/A D46A Trainer 04 text
N/A N/A D46B Trainer 05 turning data
N/A N/A D46C Trainer 05 text
N/A N/A D46D Trainer 06 turning data
N/A N/A D46E Trainer 06 text
D12B Species byte 2 D46F Trainer 07 turning data
D12C Current HP byte 1 D470 Trainer 07 text
D12D Current HP byte 2 D471 Trainer 08 turning data
D12E Level (possibly) D472 Trainer 08 text
D12F Status ailment D473 Trainer 09 turning data
D130 Type 1 D474 Trainer 09 text
D131 Type 2 D475 Trainer 10 turning data
D132 Catch rate D476 Trainer 10 text
D13F Attack experience byte 2 D483 Pokémon 1 species
D140 Defense experience byte 1 D484 Pokémon 1 level
D141 Defense experience byte 2 D485 Pokémon 2 species
D142 Speed experience byte 1 D486 Pokémon 2 level
D143 Speed experience byte 2 D487 Pokémon 3 species
D144 Special experience byte 1 D488 Pokémon 3 level
D145 Special experience byte 2 D489 Pokémon 4 species
D146 Attack & Defense DV D48A Pokémon 4 level
D147 Speed & Special DV D48B Pokémon 5 species
D148 PP of move 1 D48C Pokémon 5 level
D149 PP of move 2 D48D Pokémon 6 species
D14A PP of move 3 D48E Pokémon 6 level
D14B PP of move 4 D48F Pokémon 7 species
D14C Pokémon level D490 Pokémon 7 level
D14D Max HP byte 1 D491 Pokémon 8 species
D14E Max HP byte 2 D492 Pokémon 8 level
D14F Attack byte 1 D493 (unconfirmed) Pokémon 9 species
D150 Attack byte 2 D494 (unconfirmed) Pokémon 9 level
D151 Defense byte 1 D495 Pokémon 10 species
D152 Defense byte 2 D496 Pokémon 10 level

Example

Let's say you want specific Pokémon for Trainer IDs 02 through to 07 as such.

ID 02: Level 1 Mew ID 03: Level 254 Mewtwo ID 04: Level 5 Articuno ID 05: Level 5 Zapdos ID 06: Level 5 Moltres ID 07: Level 100 Porygon

This would require the following data from address D141:

15 01 83 FE 4A 05 4B 05 49 05 AA 64

And that is:

  • Defense experience is 21 modulo 256.
  • Speed experience is exactly 387.
  • Special experience is 65098.
  • Defense DV is 5, Attack DV is 0.
  • Speed DV is 11, Attack DV is 4.
  • Move 1 PP is 5.
  • Move 2 PP is 73.
  • Move 3 PP is 5.
  • Move 4 PP is 42 w/2(?) PP Ups used.
  • Pokémon is level 100.

Those requirements are totally unviable for non-cheat play, so it's a proof of concept, but you can get cool results with random Pokémon.

YouTube video

YouTube video by ChickasaurusGL
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