Hackmons are Pokemon that have Moves/Abilities it won't usually know. Like Blissey having Imposter, Giratina having Prankster, and Deoxys-S having Spore.
In Balanced Hackmons, you're allowed to use any move and ability on
any Pokémon, even if they don't ordinarily have said move or ability.
In addition, each Pokémon may have 252 EVs in every stat, which makes
the metagame a lot more bulky.- Smogon
