Rapidash isn't *awful* as long as you go 252 Atk / 252 Spe and spam Flare Blitz... But Talonflame Smogonbird does that better. Bulky physical ground types like Gliscor or Landorus-T also wreck Mawile. If you're good at mind games, you can set up Swords Dance or Sub on someone like Smogonbird or Bisharp and out-priority Mawile.