>>245905711. M-Glalie's Explosion
2. M-Charizard Y's Blast Burn (Sun)
3. M-Medicham's Focus Punch
4. M-Gardevoir's Hyper Beam
5. M-Pinsir's Giga Impact
6. M-Kangaskhan's Giga Impact
Used Arceus for all calcs, but changed the type to make it neutral effectiveness, so ignore that it says Arceus-Fighting. and for some reason theres no blast burn in the damage calc, so I just changed fire blast to 150BP.
>252+ Atk Refrigerate Mega Glalie Explosion vs. 252 HP / 252 Def Arceus-Fighting: 382-451 (86 - 101.5%) -- 12.5% chance to OHKO>252+ SpA Mega Charizard Y Fire Blast vs. 252 HP / 252 SpD Arceus-Fighting in Sun: 328-387 (73.8 - 87.1%) -- guaranteed 2HKO>252+ Atk Pure Power Mega Medicham Focus Punch vs. 252 HP / 252 Def Arceus-Fighting: 312-367 (70.2 - 82.6%) -- guaranteed 2HKO>252+ SpA Pixilate Mega Gardevoir Hyper Beam vs. 252 HP / 252 SpD Arceus-Fighting: 291-343 (65.5 - 77.2%) -- guaranteed 2HKO>252+ Atk Aerilate Mega Pinsir Giga Impact vs. 252 HP / 252 Def Arceus-Fighting: 277-327 (62.3 - 73.6%) -- guaranteed 2HKO>252+ Atk Parental Bond Mega Kangaskhan Giga Impact vs. 252 HP / 252 Def Arceus-Fighting: 274-324 (61.7 - 72.9%) -- guaranteed 2HKO