In FireRed and LeafGreen, it will hatch at level 77, and if raised one level, it will jump to level 100. However, when traded to Ruby, Sapphire, and Emerald, if given a Rare Candy before raising it a level, it will go down to level 45. If - is given another Rare Candy, it will grow to level 100. Afterwards, the game may lose focus as if it is frozen (the reset button combination will not work). However, after a while, the game will gain focus and "un-freeze". It can then be traded back to FireRed or LeafGreen. It has a glitch-name ability with an unknown effect, and its two types are Tough and Cute, which are Contest-only move types. -'s summary can only be viewed in Pokémon Ruby, Sapphire and Emerald, but when - is viewed in Ruby and Sapphire, the game will stay on a black screen for a while before its summary is displayed. If the player attempts to view it in Pokémon FireRed and LeafGreen the game hangs with a magenta screen. No action can be performed and the game will need to be turned off and back on.
The games treat it both like an Egg and a Pokémon. If entered in a battle as the first Pokémon in the party, the second Pokémon will be sent out instead. However, it is possible to shift - into battle. Furthermore, if taken to the Name Rater to be nicknamed, the Name Rater states that he cannot nickname an Egg. If hatched in FireRed or LeafGreen, however, it can be given a nickname when it hatches.