????? 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 4 to 15. As it is leveled up, its total experience points will repeatedly overflow; at level 100, its total experience points will be displayed as 1,110,639.
????? can only be leveled up normally 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 6. When it levels up this way, it will attempt to learn its entire level-up moveset, including moves learned past level 100. This can potentially freeze the game, as ????? learns a glitch move at level 62 that sometimes freezes the game if there are no empty slots in ?????'s moveset.
If ????? is deposited and withdrawn, it will also revert to level 6, but will not act as if it leveled up.