This would be hilariously broken lol
252+ Atk Choice Band Regigigas Return vs. 252 HP / 252+ Def Landorus-T: 247-292 (64.6 - 76.4%) -- guaranteed 2HKO after Leftovers recovery
+1 252+ Atk Choice Band Regigigas Return vs. 252 HP / 252+ Def Mega Venusaur: 298-352 (81.8 - 96.7%) -- guaranteed 2HKO
+1 252+ Atk Choice Band Regigigas Return vs. 252 HP / 144+ Def Hippowdon: 336-396 (80 - 94.2%) -- guaranteed 2HKO after Leftovers recovery
+1 252+ Atk Choice Band Regigigas Superpower vs. 252 HP / 252+ Def Skarmory: 214-252 (64 - 75.4%) -- guaranteed 2HKO
+1 252+ Atk Choice Band Regigigas Return vs. 0 HP / 0 Def Mega Altaria: 442-522 (151.8 - 179.3%) -- guaranteed OHKO
252+ Atk Choice Band Regigigas Return vs. 48 HP / 0 Def Mega Salamence: 255-301 (74.3 - 87.7%) -- guaranteed 2HKO
252+ Atk Choice Band Regigigas Return vs. 252 HP / 252+ Def Landorus-T: 247-292 (64.6 - 76.4%) -- guaranteed 2HKO after Leftovers recovery
+1 252+ Atk Choice Band Regigigas Return vs. 252 HP / 252+ Def Mega Venusaur: 298-352 (81.8 - 96.7%) -- guaranteed 2HKO
+1 252+ Atk Choice Band Regigigas Return vs. 252 HP / 144+ Def Hippowdon: 336-396 (80 - 94.2%) -- guaranteed 2HKO after Leftovers recovery
+1 252+ Atk Choice Band Regigigas Superpower vs. 252 HP / 252+ Def Skarmory: 214-252 (64 - 75.4%) -- guaranteed 2HKO
+1 252+ Atk Choice Band Regigigas Return vs. 0 HP / 0 Def Mega Altaria: 442-522 (151.8 - 179.3%) -- guaranteed OHKO
252+ Atk Choice Band Regigigas Return vs. 48 HP / 0 Def Mega Salamence: 255-301 (74.3 - 87.7%) -- guaranteed 2HKO