??????????, also known as ten question marks or its fan-given nickname, Decamark(s), is a glitch Pokémon that occupies slot 0000, and all slots above 019D in Ruby, Sapphire, Emerald, FireRed, and LeafGreen. It was programmed into the game to prevent game crashes and is technically not a glitch Pokémon because its information was defined by the programmers. However, ?????????? can also occupy other values of the 65536 slots available as well as cause glitchy behavior in games, some specific versions may even freeze the game, such as hex DEFD.
??????????'s sprite usually appears as three concentric circles alternating between white and black around a question mark in the center, this graphic was used to represent that a Pokémon that is not seen on a pokédex. Whereas index number 0000 and other ?????????? usually use Bulbasaur's footprint, there are a few which use other Pokémon's footprints.
?????????? hex 0000 form cannot be obtained, as it disappears from a party when caught.
In the Generation I and II games, Pokémon index numbers range from 00 to FF, totaling to exactly 256 Pokémon slots available. In the Generation III games, Pokémon index numbers range from 0000 to FFFF, allowing 65536 Pokémon to be defined; however, only 439 (counting Egg, Unown forms, Deoxys Formes, and 25 ?) were defined, filling the remaining 65,097 slots with ?????????? variants.
This glitch data is most commonly encountered in-game by using a GameShark or Action Replay code for a Pokémon that doesn't exist. However, there are several other methods for encountering ??????????.
A GameShark code can be used to quickly level-up a Pokémon in FireRed and LeafGreen's Pokémon Day Care. If any Pokémon is placed into the Pokémon Day Care before the code is activated, after walking around for a short time, the Pokémon in the Pokémon Day Care will produce an Egg all by itself. The Egg will soon hatch into a level 0 ??????????; however, ?????????? requires 1,000,000 EXP points to reach level 1, making it tedious to level up without using a Rare Candy.
If ?????????? is traded to Pokémon Emerald, it can be left in the Pokémon Day Care and will instantly grow to level 100. At this point, it can learn any of the eight HM moves via HM and will be safe for the game unless its summary is looked at. If given Rare Candies, it will start rapidly learning Ice Punch, even if the player refuses to teach it. This can be fixed by activating the "access fly map" GameShark code. ??????????'s National Pokédex number can vary, ranging from 0 to over 386, depending on its hexadecimal identifier. If the hexadecimal identifier number is over 1000, then a ? mark replaces the hundreds column (e.g. ?24).
The summary that doesn't freeze the game, viewed in Pokémon FireRed and LeafGreen. Note the backwards question mark (since summery screen flips the Pokémon sprite horizontally).
Another method for obtaining ?????????? is to use an Action Replay code to teleport or walk through walls to an area where a wild Pokémon can be captured before getting a starter Pokémon from either Professor Birch in Pokémon Ruby, Sapphire, and Emerald or Professor Oak in Pokémon FireRed and LeafGreen. If a wild Pokémon battle is initiated, the player will send out a ?????????? with 0/0 HP and with a hexadecimal identifier of 0. If the Pokémon gets hit, the player will white out and be sent to a Pokémon Center where 65536 Poké Balls will begin to appear in seemingly random locations in a horizontal line all across the screen (this is because the game will refer to the number 0 as one more than a full two bytes (65535)). A very similar effect occurs when one performs a variation of the Pomeg glitch; when the Pokémon's HP goes below 0 it will skip to the largest value. This system uses two bytes, so the Pokémon's HP will start to drop down from 65535.
After this Pokémon is captured, if one chooses to nickname ?????????? or looks at it in the party screen, its sprite may appear as a gold-colored Bulbasaur. This is due to using icon palette 0 in place of an undefined palette. Another way to see this glitch is to use the "walk through walls" code, go to the Link Cable area, and battle. Since there is no connected opponent, this glitch appears instead (as value 000).
Pre-National Pokédex method
A third way to obtain ?????????? is to use a GameShark or Action Replay to catch a Pokémon not native to the Hoenn region in its original area before obtaining the National Pokédex as the game would search for a Pokémon using the Regional Pokédex number rather than the National Pokédex number; for example, if the player was to normally encounter a Yanma, instead the game would search for a Pokémon with a Regional Pokédex value of 193, possibly resulting in an encounter of another variety of this glitch with a different moveset and Ability or a Regirock in Ruby, Sapphire, and Emerald Versions.
?????????? may hold an item. The item will be called ???????? (eight marks), with a description in the Bag of ????? (five marks). The item can only make a Pokémon that is holding it become glitched if migrated to Pokémon Diamond or Pearl. If the player tries to use it, Professor Oak will say that "the time isn't right" to use it. With the help of a GameShark, it can be bought at a Poké Mart for 0 but cannot be sold, as the Poké Mart cashier will say, "Oh, no. I can't buy that."
??????????'s learnset varies by game and by hexadecimal identifier. Due to the existence of several thousand different species between games, the full information cannot be listed here.
Some ?????????? have no moves. When this happens, attempting to attack with it will result in it using Struggle. However, viewing the Pokémon's moves page will show a large amount of glitch text, although this text is not known to cause any side effects.
Many variations of ?????????? are named after moves or fragments of a move's name (truncated to the game maximum of ten characters) (e.g. POUND, RBOLT, ING ATTACK, ICK ATTACK, and so on.) This is due to the hexadecimal identifier of the variation calling for a name from text just past where Pokémon names are stored, which is where move names are stored.
One can only view these names when nicknaming the Pokémon or in the PC.
For higher numbers, the names stop being valid strings. Trying to nickname that Pokémon will result in the game crashing with glitch noises, or sometimes just freezing.
The project "Melchior X" on Glitch City Laboratories is dedicated to the research of the 65,097 variations of ??????????, although this is not expected to be completed in the near future and it is also archived.