>>18165942+2 252 Atk Mega Pinsir Earthquake vs. 252 HP / 0 Def Filter Mega Aggron: 178-210 (51.7 - 61%)
0 Atk Mega Aggron Stone Edge vs. 4 HP / 0 Def Mega Pinsir: 332-392 (122 - 144.1%)
252 Atk Choice Band Talonflame Flare Blitz vs. 252 HP / 0 Def Filter Mega Aggron: 153-181 (44.4 - 52.6%)
0 Atk Mega Aggron Stone Edge vs. 4 HP / 0 Def Talonflame: 512-604 (171.8 - 202.6%)
252 Atk Choice Band Staraptor Close Combat vs. 252 HP / 0 Def Filter Mega Aggron: 133-157 (38.6 - 45.6%)
0 Atk Mega Aggron Heavy Slam (120 BP) vs. -1 4 HP / 0 Def Staraptor: 348-411 (111.5 - 131.7%)
252 Atk Choice Band Terrakion Close Combat vs. 252 HP / 0 Def Filter Mega Aggron: 208-247 (60.4 - 71.8%)
0 Atk Mega Aggron Earthquake vs. -1 0 HP / 0 Def Terrakion: 316-372 (97.8 - 115.1%)
It has a hard time countering stuff (especially since it has to mega evolve first) but 70/230 bulk with filter is enourmous bulk, very few physical attackers can break through it in one hit even with boosts.
252 Atk Pure Power Mega Medicham High Jump Kick vs. 252 HP / 0 Def Filter Mega Aggron: 253-298 (73.5 - 86.6%)
252+ Atk Mega Aggron Heavy Slam (120 BP) vs. 0 HP / 0 Def Mega Medicham: 261-307 (100 - 117.6%)
That's the most powerful, unbanded and unboosted attack in the entire game, and it doesn't OHKO Mega Aggron even for SE damage. Mega Aggron is able to OHKO back with Heavy Slam so long as it has attack investment.
+1 252 Atk Tough Claws Mega Charizard X Flare Blitz vs. 252 HP / 0 Def Filter Mega Aggron: 274-324 (79.6 - 94.1%)
252+ Atk Mega Aggron Earthquake vs. 4 HP / 0 Def Mega Charizard X: 232-274 (77.8 - 91.9%)
Even the most fearsome Dragon Dancer loses 1v1, adding in Flare Blitz recoil damage.
If all else fails you can Paralyze stuff, pretty much ending any potential sweeps.
