- Main article: Time Capsule exploit
????? will act as 'cancel' on the party Pokémon screen. ????? cannot be healed via a Pokémon Center as the game will take it to be the end Pokémon slot. Therefore, if ????? is placed above other Pokémon in the party screen, those Pokémon also cannot be healed. However, ????? and the Pokémon below it can be healed with items.
This type of ????? cannot be deposited because it will replace itself and all Pokémon below it with "CANCEL".
????? can be taken into the Time Capsule to 'hide' the Pokémon below it which did not exist in Generation I. "CANCEL" is allowed through the time machine because it is essential on all Generation I and Generation II Pokémon games. Any Pokémon below it will appear as 'M (00)RB or 3TrainerPoké $Y.
????? has a glitched experience group that causes the amount of experience it needs to level up to underflow. Since unsigned integers are used, the game will interpret this number as a number close to 16,777,162, causing ????? to require that much experience points to level up to any level from 3 to 57. As it is leveled up, its total experience points will repeatedly underflow; at level 100, its total experience points will be displayed as 127,800, despite requiring many times that experience to reach level 100. ????? can only be leveled up through the use of Rare Candies; if ????? is leveled up in battle, it will level up to level 255, underflow to level 1, and settle on level 3.