I will insist with the problem of (Foul Play) now there are people using 4-5 Pokémon with that movement ... Destroy Pokémon (Spatk) ... As if nothing
Well insist, I agree with my friends and especially with my cousin (Foul Play - not based on the "Def" / "HP" / or "Spatk" of the Pokémon - only and exclusively (Atk) and only, if only the adversary uses increment of said "Atk" with one movement - increases the damage of "Foul Play".
Does not adhere to - Ability or Equipped Object.
I have shown that the game in (console) "Pokemon / Black And White" that is 5 generation and (Sun and Moon) has never shown that mode of (hit) the movement "Foul Play"