Glitch City Laboratories Archives

Glitch City Laboratories closed on 1 September 2020 (announcement). This is an archived copy of an article from Glitch City Laboratories wiki.

A live version of this article is available at the Glitch City Wiki here.

You can join Glitch City Research Institute to ask questions or discuss current developments.

You may also download the archive of the wiki in .tar.gz or .xml.gz formats.

Bad clone glitch

Major glitches of the Pokémon series

Arbitrary code execution

0x1500 control code arbitrary code execution (Crystal) | Cart-swap arbitrary code execution | Generation I custom map script pointer | Generation I invalid meta-map scripts | Generation I item ("8F", "ws m", "-g m", "5かい", "てへ" etc.) | Generation I move ("-", "TM42") | Generation I Trainer escape glitch text boxes | Generation II bad clone | Generation II Burned Tower Silver | Japanese Crystal Pokémon Communication Center SRAM glitches | Coin Case glitch | Generation II glitch Pokédex sortings | Pikachu off-screen glitch ACE | OAM DMA hijacking | Pikachu glitch emote | Generation III glitch Pokémon summary | Generation III glitch move animation) | Remote code execution | TM/HMs outside of the TM/HM pocket | ZZAZZ glitch Trainer FC

[hr] No further extensions

Cloning | Item duplication glitch (Generation I) | Pokémon merge glitch ("Q Glitch", Generation I) | Time Capsule exploit | Bug-Catching Contest data copy glitch (Generation II, Japan only) | Berry glitch | Battle Tower Lati@s glitch (Generation III) | (Mimic) Transform Rage glitch (Generation IV)

Transform held item glitch (Generation IV, Japan only) | Mimic glitch (Generation IV, Japan only)

[hr] Buffer overflow techniques

99 item stack glitch | LOL glitch | Rival LOL glitch | Instant LOL glitch | RAM LOL glitch | Out of bounds LOL glitch | blockoobLG | Instant encounter infinite chain glitch | LGFly | Super Glitch (Generation I) | Party remaining HP glitch | Super Glitch (Generation III) | Text pointer manipulation mart buffer overflow glitch | CoolTrainer♀-type move | Double distort CoolTrainer♀ corruption | Yami Shop glitch | Party Pokémon box data shift glitch | Unterminated name glitch item instant encounter (Japanese Red/Green)

[hr] Item stack duplication glitch (Generation I)

Generation I expanded items pack (Glitch Rocket HQ maps, Map FE (English and non-English European Yellow) | Map script pointer manipulation (arbitrary code execution | Map script pointer item ball manipulation) | Text pointer manipulation (arbitrary code execution | Item ball manipulation | Mart buffer overflow) | Trainerless instant encounter glitch

[hr] Bad clone glitch (Generation II)

????? party overloading (Type 0xD0 move glitch | ????? map corruption | Celebi trick | Celebi Egg trick | Shiny Celebi trick | Glitch move map corruption | Overloaded party map corruption | Glitch Unown (Glitch Unown map corruption) | Duplicate key items glitch (Infinite items and item creation, Expanded Balls pocket (Wrong pocket TM/HMs, Glitch Pokédex categories))

[hr] Closed menu Select glitches (Japanese Red/Green)

Dokokashira door glitch (International) | Fossil conversion glitch (international) | Second type glitch | Skip to Level 100 glitch | Trainer mutation glitch | Walk through walls (International) | Lift glitch | Badge describer glitch

[hr] Pomeg glitch (Generation III)

Pomeg data corruption glitch ("Glitzer Popping") | Charm glitch

[hr] Voiding (Generation IV)


Broken escalator glitch (Japan only) | Elite Four door glitch (Japan only)

[hr] 2x2 block encounter glitches (Generation I)

Left-facing shore tile glitch (in-game trade shore encounter trick, Old man trick, Trade link up shore encounter trick, Fight Safari Zone Pokémon trick) | Viridian Forest no encounter grass tiles glitch

[hr] Glitch City

Safari Zone exit glitch | RAM manipulation | Out of bounds Glitch City (Generation II) | Slowpoke Well out of bounds corruption (French Gold/Silver/Crystal)

[hr] Large storage box byte shift glitch

Storage box remaining HP glitch | Generation I max stat trick

[hr] Pikachu off-screen glitch

Trainer corruption glitch

[hr] SRAM glitches

Generation I save corruption | 255 Pokémon glitch | Expanded party encounter table manipulation (Generation I) | Send party Pokémon to a new game (Generation I) | Generation II save corruption | Mailbox glitches | Mystery Gift item corruption | Trainer House glitches

[hr] Trainer escape glitch

Death-warp | Ditto trick | Experience underflow glitch | Mew trick | Text box ID matching | Meta-map script activation

[hr] Walk through walls

Ledge method | Museum guy method | Rival's effect | Select glitch method (International Select glitch method), Brock Through Walls

[hr] Surf down glitch

Grass/rock Surfing glitch (Spanish/Italian only) (adaptions: Submerge glitch (international)) | 8 8 (0x7C) grass/rock surfing glitch (English Red/Blue))

(view, talk, edit)

PRAMA Initiative a également une page sur .
The bad clone glitch is a natural glitch in Pokémon Gold, Silver and Crystal that allows the player to obtain an unstable hybrid Pokémon known as a bad clone. By allowing the player to stabilize the bad clone into a ?????, it is the parent glitch of many other glitches such as ????? party overloading or Time Capsule exploit. It is named as such because it can happen when doing the Gold/Silver/Crystal cloning glitch.

Obtaining a bad clone

More research is needed for this article.

Reason given: Document more effects of it. Can a Glitch Pokémon evolve if its sprite and name are "stable" enough? Are there many glitch cries available for Glitch Pokémon? List Glitch Type Sprites that could cause interesting effects. Study the causes and effects of the corruption of the PC Pokémon Selection in Fr/Lg. Test again the effect of Pokédex entries of Glitch Pokémon.

In order to get a bad clone you should deposit more Pokémon than you have ever deposited in a box (and at least 5 or so), then change boxes and reset the game at the following exact timing:
  • Shortly after the Yes/No box disappears (Gold/Silver)
  • After SAVING... DON'T TURN OFF THE POWER. is fully printed (Crystal) Notice that on the Game Boy Player (common for speedruns), the reset fadeout delay applies, so the timing to press the reset button is different:
  • Immediately after pressing A on "Yes" (Gold/Silver)
  • After the second "F" in "SAVING ... DON'T TURN OFF THE POWER." (Crystal)

    Getting a bad clone can normally be very difficult without Pokémon Stadium 2, but Pokémon Stadium 2's Game Boy Tower makes it a lot easier if you reset the game after the "Saving..." message appears at one of the aforementioned moments.

    Another way to get a bad clone in BGB emulator in English Pokémon Gold, Crystal is to do it with five Pokémon deposited into box 4, set a breakpoint for de=AD6D (Gold) or de=AD11 (Crystal), advance the execution flow with F7 and then reset the game.

    To identify a bad clone, the bad clone may be female with a glitched name and become level 1 after you withdraw it from the PC. Contrary to the belief of some, if the original Pokémon was female it is still possible for the bad clone to be female (not male), although it is a good idea to use a male Pokémon in order to more easily identify a bad clone in case there are other male Pokémon in the box.

    Properties of the bad clone

    A "real" bad clone is an unstable hybrid between the cloned Pokémon and a ????? (hex 00). It is sometimes referred to as a glitched version of the original Pokémon; for example, a "glitched Sneasel".

    The bad clone will usually have a nickname with a large amount of glitch text. It usually is female and level 0 in the PC, but will become level 1 after you withdraw it. It usually has no moves, but sometimes may have glitched moves, and on rare occasions cannot be withdrawn from the PC [clarification needed].


    The bad clone glitch happens when the game is reset in the middle of saving the contents of a box. The Gen II box data structure is as follows:

    Box Pokémon count (1 byte) Box Pokémon 1 species (1 byte) Box Pokémon 2 species (1 byte) ... Box Pokémon 20 species (1 byte) Extra space used for end-of-box marker (1 byte) Box Pokémon 1 data (32 bytes) Box Pokémon 2 data (32 bytes) ... Box Pokémon 20 data (32 bytes) Box Pokémon 1 OT name (11 bytes) Box Pokémon 2 OT name (11 bytes) ... Box Pokémon 20 OT name (11 bytes) Box Pokémon 1 nickname (11 bytes) Box Pokémon 2 nickname (11 bytes) ... Box Pokémon 20 nickname (11 bytes) Unused (2 bytes)

    Of course, the species list is usually redundant since the species information is stored in the 32-byte Box Pokémon data struct (one exception is when the Pokémon is an egg, the species list will have EGG (hex FD) while the data struct has the real species). Such a redundancy occurs similarly in the party data structure. Hybrid Pokémon happens when those two species bytes disagree with each other.

    In the simplest form of the bad clone glitch, one more Pokémon (say, Pokémon 18) is added to the box, then the saving of the box is interrupted by a hard reset. If the reset happens after the box count and the species byte of that Pokémon is written, but before the main data of that Pokémon are written (for example, it happens right in the middle of "Box Pokémon 15 data"), then the PC will recognize the existence of a 18th Pokémon and know its species, but its main data, OT name, and nickname will remain uninitialized. (In this case, no other Pokémon's data is corrupted, not even Pokémon 15 — the game is interrupted when overwriting the "Box Pokémon 15 data" with the exact same data.)

    Uninitialized SRAM data on a real cartridge can be non-deterministic, and emulators also have different behaviors in this regard. However, one way to be sure of the data is to clear the save data (by Select + Up + B on the title screen) before playing the game, which fills the entire SRAM with 00. If we do this, then those uninitialized data is guaranteed to be 00 — even if we put Pokémon in the box then withdraw them, the 00 sections under them will "shift up" — with the exception that if a box has ever been completely full, then when withdrawing from it, the last Pokémon's data will "shift up" instead of 00 sections. This is why such boxes are unsuitable for getting bad clones (although they may be useful in getting other hybrids).

    Anyway, in this case, the Pokémon will have all of its main data, including the second species byte, be 00. Such a Pokémon will exhibit all the properties of a typical bad clone: Female, level 0, stabilizes into a ????? (hex 00), etc.


    A "real" bad clone can be taken into the Day Care and out to become a ????? (hex 00). Using the ????? party overloading trick will allow the player to perform various glitches, including:

  • Celebi trick, Celebi Egg trick, Shiny Celebi trick, etc. (a result of removing an FF terminator from the party and performing data shifts).
  • Converting a ????? (hex 00) into a ????? (hex FF) for use with the Time Capsule exploit.
  • ????? map corruption
  • Obtaining Glitch Unown

    Unterminated name exploits

    Main article: Coin Case glitch Bad clones with unterminated names can also be used for various other exploits, notably 0x1500 control code arbitrary code execution.