Does Golurk's "Superpower" attack apply Resistance to the +20 damage it does to itself?
Yes, as long as Golurk is Fighting Type at the time of the attack, Resistance would be applied.
Superpower




×2
Knuckle Punch

SuperpowerYou may do 30 more damage. If you do, this Pokémon also does 30 damage to itself.
This Pokémon is so muscular and strongly built that even a group of wrestlers could not make it budge an inch.
Does Golurk's "Superpower" attack apply Resistance to the +20 damage it does to itself?
Yes, as long as Golurk is Fighting Type at the time of the attack, Resistance would be applied.