Except it can't really.
+2 252+ Atk Huge Power Mega Mawile Fire Fang vs. 252 HP / 232+ Def Skarmory: 308-364 (92.2 - 108.9%) -- guaranteed OHKO after Stealth Rock
Switch mawile in on something that is forced out, swords dance on the obvious skarmory switch and then OHKO with fire fang if rocks are up. Still has a 50% chance to OHKO without rocks. Don't underestimate how easy it is for mega mawile to get a free swords dance boost. It can OHKO garchomp with its "weak" priority after a swords dance.
+2 252+ Atk Huge Power Mega Mawile Fire Fang vs. 252 HP / 232+ Def Skarmory: 308-364 (92.2 - 108.9%) -- guaranteed OHKO after Stealth Rock
Switch mawile in on something that is forced out, swords dance on the obvious skarmory switch and then OHKO with fire fang if rocks are up. Still has a 50% chance to OHKO without rocks. Don't underestimate how easy it is for mega mawile to get a free swords dance boost. It can OHKO garchomp with its "weak" priority after a swords dance.