??????????, colloquially known as Decamark, is a Glitch Pokémon found in the Game Boy Advance Pokémon games. Generally, it cannot be encountered without the use of a GameShark. It is often seen acting as a placeholder, and it mostly consists of empty data.

In the Pokédex, Pokémon that have not yet been seen are displayed with "----------" as their name; their sprite is a black-and-white bulls-eye with a question mark in it. ?????????? uses this same sprite, and when caught, its name in the Pokédex is shown as "----------". Its description, too, is a possible placeholder: "This is a newly discovered Pokémon. It is currently under investigation. No information is available at this time."

Empty slots in a player's party are actually ??????????. This can be demonstrated with a GameShark; if the player uses a walk-through-walls code to start a wild battle without having received a Starter Pokémon, then at the start of that battle, the player will send out a ??????????. The ?????????? typically seen in cases like this have 0 max HP, no moves, and no displayed moves; the player will white out as soon as the ?????????? is attacked.