32 Atk Diancie Diamond Storm vs. 0 HP / 0 Def Thundurus: 300-354 (100.3 - 118.3%) -- guaranteed OHKO
0- Atk Diancie Diamond Storm vs. 0 HP / 0 Def Thundurus: 260-308 (86.9 - 103%) -- 18.8% chance to OHKO
252 SpA Thundurus Thunderbolt vs. 252 HP / 224+ SpD Diancie: 79-94 (25.9 - 30.9%) -- 4.7% chance to 4HKO after Leftovers recovery
+2 252 SpA Thundurus Thunderbolt vs. 252 HP / 224+ SpD Diancie: 157-186 (51.6 - 61.1%) -- 94.1% chance to 2HKO after Leftovers recovery
+2 252 SpA Thundurus Thunderbolt vs. 252 HP / 252+ SpD Diancie: 154-183 (50.6 - 60.1%) -- 85.9% chance to 2HKO after Leftovers recovery
(this one was removed from the thundurus set but it's still noteworthy) 252 SpA Thundurus Grass Knot (20 BP) vs. 252 HP / 224+ SpD Diancie: 24-30 (7.8 - 9.8%) -- possibly the worst move ever