I've found this to be an amazing counter to any set up including Clefable, Mega Sableye and Aegislash.
EV's 252 HP/4 Def/252 Spe
Drain punch/Sucker punch/Rapid spin
-Trick locks them into a specific (hopefully status) move
-Skill swap makes their stats decrease when they use moves like stockpile or dragon dance (it also works on Pokemon with Magic bounce because it just forces the foe to use Skill swap instead
-This is your offensive move just so that you aren't completely useless late game. Take your pick. I like drain punch for the sustain
-Teeter dance confuses everyone, Encore locks them into a move if you have already tricked off your scarf, and disable makes the tanks even more useless. again, take your pick
If you see something that you suspect to be a set up Pokemon, just switch in and screw with them