I'd like to remind some people that

now gets Sword Dance and to show you calcs with it.
+2 252+ Atk Lopunny-Mega Close Combat vs. 252 HP / 4 Def Filter Aggron-Mega: 316-375 (91.8 - 109%) -- 50% chance to OHKO
+2 252+ Atk Lopunny-Mega Return vs. 248 HP / 112+ Def Slowbro-Mega: 193-228 (49.1 - 58%) -- 96.9% chance to 2HKO
+2 252+ Atk Lopunny-Mega Return vs. 252 HP / 252+ Def Unaware Clefable: 166-196 (42.1 - 49.7%) -- guaranteed 3HKO
+2 252+ Atk Lopunny-Mega Close Combat vs. 252 HP / 252+ Def Skarmory: 253-298 (75.7 - 89.2%) -- 12.5% chance to OHKO after Stealth Rock
+2 252+ Atk Lopunny-Mega Quick Attack vs. 0 HP / 4 Def Alakazam-Mega: 211-249 (84 - 99.2%) -- 75% chance to OHKO after Stealth Rock
+2 252+ Atk Lopunny-Mega Mach Punch vs. 0 HP / 0 Def Greninja-Mega: 372-438 (130.5 - 153.6%) -- guaranteed OHKO
+2 252+ Atk Lopunny-Mega Mach Punch vs. 0 HP / 0 Def Aerodactyl-Mega: 171-202 (56.8 - 67.1%) -- guaranteed 2HKO after Stealth Rock
Mega Lopunny is cooking the entire Meta. If you let Sword Dance one (very easy in this economy when you have Parting Shot Sableye) it can run through 99% of the available Pokemon.
The 1% that aren't immediately eviscerated are Mega Slowbro and Clefable who is playing as the Gen 8 Ubers Quagsire role where 1 slip up or some bad luck, you lose your Clefable.
So basically you just have Mega Slowbro as an answer.
Now if only there was a Dark type with massive SpA to target Slowbro's frailer defenses and good special bulk allowing it to switch in easily...

Oh wait