>>30113758No boosts
252+ Atk Mega Rayquaza Dragon Ascent vs. 252 HP / 0 Def Zygarde: 234-276 (36.7 - 43.3%) -- 99.3% chance to 3HKO after Leftovers recovery
0 Atk Zygarde Thousand Arrows vs. 0 HP / 4 Def Mega Rayquaza: 97-115 (27.6 - 32.7%) -- guaranteed 4HKO
1 coil vs 1 dragon dance
+1 0 Atk Zygarde Thousand Arrows vs. 0 HP / 4 Def Mega Rayquaza: 144-171 (41 - 48.7%) -- guaranteed 3HKO
+1 252+ Atk Mega Rayquaza Dragon Ascent vs. +1 252 HP / 0 Def Zygarde: 234-276 (36.7 - 43.3%) -- 99.3% chance to 3HKO after Leftovers recovery
Dragons Ascent lowers defense, so Zygarde wins this one
If Mega fug uses swords dance
+2 252+ Atk Mega Rayquaza Dragon Ascent vs. +1 252 HP / 0 Def Zygarde: 312-367 (49 - 57.7%) -- 56.3% chance to 2HKO after Leftovers recovery
If we put investment into attack, without any coils, Zygarde can 3hko Megafug, with a coil up he can 2hko megafug. After a Dragons Ascent, thousand arrows has a 12% to ohko, with stealth rocks up its a 1hko.
If we put 100 ev's into zygards defense
+2 252+ Atk Mega Rayquaza Dragon Ascent vs. +1 252 HP / 100 Def Zygarde: 286-337 (44.9 - 52.9%) -- guaranteed 3HKO after Leftovers recovery
Putting the rest into attack, thousand arrow will 1hko after 2 dragons ascents.
Rest/sleeptalk/coil/thousand arrows
252hp/152atk/100def
This requires a bit of set up so its no megafug counter, but its one of the few pokemon that can challenge it.