>>21057773>Mega Flareon with 230 base Attack using a base 104 power attack at +2 priority with STAB252+ Atk Flareon Extreme Speed vs. 252 HP / 252+ Def Deoxys-D: 150-177 (49.3 - 58.2%) -- 97.7% chance to 2HKO
252+ Atk Flareon Extreme Speed vs. 252 HP / 252+ Def Avalugg: 270-318 (68.5 - 80.7%) -- guaranteed 2HKO after Leftovers recovery
252+ Atk Flareon Extreme Speed vs. 252 HP / 252+ Def Skarmory: 330-390 (98.8 - 116.7%) -- 87.5% chance to OHKO
252+ Atk Flareon Extreme Speed vs. 252 HP / 252+ Def Cloyster: 136-162 (44.7 - 53.2%) -- 31.3% chance to 2HKO
actually that's still kind of underwhelming...