+1 252+ Atk Mega Gyarados Waterfall vs. 252 HP / 252+ Def Mega Aggron: 94-112 (27.3 - 32.5%)

+1 252+ Atk Mega Gyarados Waterfall vs. 252 HP / 252+ Def Regirock: 106-126 (29.1 - 34.6%) (neutral damage for comparison purposes)

+1 252+ Atk Mega Gyarados Waterfall vs. 252 HP / 252+ Def Avalugg: 114-135 (28.9 - 34.2%)

+1 252+ Atk Mega Gyarados Waterfall vs. 252 HP / 252+ Def Cresselia: 156-184 (35.1 - 41.4%)

+1 252+ Atk Mega Gyarados Waterfall vs. 252 HP / 252+ Def Mandibuzz: 171-202 (40.3 - 47.6%)

+1 252+ Atk Mega Gyarados Waterfall vs. 252 HP / 252+ Def Giratina: 156-184 (30.9 - 36.5%) (again, neutral damage)

Wow. This is news to me. Giratina's defenses are 150 HP / 120 Def / 120 SpDef. I thought it was the bulkiest mon in the game, but Avalugg and Mega Aggron both dethrone it.

252+ Atk Pure Power Mega Medicham High Jump Kick vs. 252 HP / 252+ Def Filter Mega Aggron: 225-265 (65.4 - 77%)

+2 252+ Atk Sand Force Mega Garchomp Earthquake vs. 252 HP / 252+ Def Filter Mega Aggron in Sand: 330-388 (95.9 - 112.7%)

+2 252+ Atk Mega Heracross Close Combat vs. 252 HP / 252+ Def Filter Mega Aggron: 325-384 (94.4 - 111.6%)

252+ Atk Choice Band Sheer Force Darmanitan Flare Blitz vs. 252 HP / 252+ Def Filter Mega Aggron: 256-303 (74.4 - 88%)

+2 252 Atk Adaptability Mega Lucario Close Combat vs. 252 HP / 252+ Def Filter Mega Aggron: 327-387 (95 - 112.5%)

+2 252+ Atk Parental Bond Mega Kangaskhan Earthquake vs. 252 HP / 252+ Def Filter Mega Aggron: 202-238 (58.7 - 69.1%)

I could go on, but...

This thing's bulk is incredible. Best physical bulk in the game, nigh impossible to OHKO without a STAB super effective hit, 140 base Attack...

Let's have a Mega Aggron discussion thread. Do you use it? If so, which tier? Is it useable in OU? Do you give it Wish support? Does it need it?

How about sets? Max HP and Attack? Defense for bulk? Special Defense to round it out?