Partially unused and glitched

Partially unused or semi-glitch things are a side effect of how data in the Pokémon games is retrieved. Functions that retrieve data may simultaneously load valid but unused data leftover from development, as well as glitch data which was never intended to be added there.

Examples

Pokémon

• The MissingNo. before index number 191 have some leftover unused but valid data.
  • Nine of them have some unused cry data. The cries for the rest is the result of all the parameters being 0 (Nidoran♂ pitch 0 and length 0 (256)).
  • There are 39 entries in between the 151 existing Pokémon. Adding these together is 190 Pokémon; a former total of Pokémon in leaked source code of Pokémon Blue. Some of the MissingNo. were once unreleased Pokémon, such as Gorochu (index number 175) before they were removed and the games were recompiled to reflect this. However, three MissingNo. (182, 183, 184) had some data repurposed for the Kabutops Fossil, Aerodactyl Fossil and Ghost front sprites. In the Pewter Museum, internally the game actually loads the Fossil MissingNo. index number to retrieve its front sprite. Note while trading MissingNo. to Pokémon Gold, Silver and Crystal results in specific Generation II Pokémon, contrary to popular belief they may not have been intentionally defined as those Pokémon/the actual Pokémon the MissingNo. were is different according to the source code leak, and some related publicly released information such as the index numbers of unused Pokémon (matching some of the MissingNo.) in the 2018 educational Satoshi Tajiri: A Man Who Created Pokémon manga.
  • The names "MISSINGNO." (けつばん) itself (and ゴースト for index number 184 (Ghost) in the Japanese versions (not to be confused with ゆうれい, the final term for Pokémon Tower ghosts)) were intentionally hard-coded into the game. This contrasts with the other glitch Pokémon such as 'M (00) which have their names as unrelated data in the game extrapolated beyond the names table.
  • All MissingNo. Pokédex numbers were to set 000, and in Japanese Pokémon Blue, MissingNo. were given the placeholder Pokédex entry "コメント さくせいちゅう" (meaning 'comment to be written') and became the ??? species. This was not translated, resulting in a glitched Pokédex entry in the localized Pokémon Red and Blue and the corruption of MissingNo.'s original height and weight (1.0 m (3.3 ft) and 10.0 kg (22.1 lb), respectively), showing instead a height of 10.0 ft (3.1 m) and a weight of 3507.2 lb (1590.8 kg).
  • No MissingNo. can learn any moves by level-up or evolve (unlike the other glitch Pokémon), however they have starting moves and learnable TM/HM moves (the results of glitch data extrapolated by Pokédex No. 000/also the reason why 'M (00) also starts with Water Gun, Water Gun, Sky Attack and not intentional).
• Many 'Pokémon' that retrieve placeholder data in general, such as ?????????? and the function to make its sprite a "?" in a circle, ? (glitch Pokémon)'s sprite; in those cases they are commonly forced as glitch Pokémon so bring some invalid data with them (such as base stats for glitch Pokémon with index numbers other than 0 and 252-276/index numbers greater than 439). Possibly - (while appearing as an Egg named "-" that partially behaves like one, it has base stats and types which are glitched and were never intentionally programmed. This is a similar case to Generation II glitch Egg before it, and its back-sprites which are glitch sprites).

Items

• The unused rank names and badges, such as かいがらバッヂ (ShellBadge) or プチマスタ (Petit Master) are a leftover from development (their names are corrupted/mojibake outside of the Japanese versions), but unintentionally can be forced as glitch items beyond the index number of the last valid non-TM/HM (Max Elixer; 0x53) with invalid effects because the data structures for the names are close together (this also applies to the names of floor destinations beginning with B2F, strings from the new name screen such as JACK, etc.)

Trainers

• While Trainer 0x00 (accessed with a Special stat of 200 during the Trainer escape glitch) is a glitch Trainer with no signs (except its placing as the first indexed Trainer counting 0x00) of ever being used in the final games, it may have belonged to an unreleased valid Trainer according to the source code leaks.
• Juggler (unused Trainer class)'s name was originally ジャック (Jack) during a period of development when he was a Trainer known as Shinjuku Jack (a reference to Takayuki Haneda, pseudonym "Shinjuku Jacky"; who mained Jacky Byran in the game Virtua Fighter by Sega) before all references to Jack were removed (except as a pre-set name) and the Trainer in his place became the unused Juggler copy. However, a list of Trainer Classes in Japanese mentioning Jack where the unused Juggler would have been remains in the final versions of Pokémon Gold and Silver Versions.
• A similar situation to the Juggler also applies to the Chief. Furthermore, some extra unused information can be retrieved from his Japanese name Silph's Chief or Silph's Manager (シルフのチーフ), possibly suggesting he was linked to the Silph Co. before being cut from the game. In the source code leak, the Chief also used Blaine's newer design (like in the final games) instead of the Scientist sprite although this did not survive by the time the final ROMs were released. (At the time, the actual Blaine had his own cut design, which can still be seen in the manuals of the final game)

Maps

• Some partially unused glitch maps, such as Map 0x0B (actual unused data include potential placeholder data (such as the music for map 0x0B matching Viridian City), the unused Fly flag for going to map 0x0B, the hidden Max Elixer in unused but glitched map 0x6F).