duckpond
There's no way
Heatran @ Leftovers
Ability: Flash Fire
EVs: 248 HP / 192 SpD / 68 Spe
Calm Nature
- Lava Plume
- Toxic
- Taunt
- Stealth Rock
Heatran can switch in every time, take nothing from Leaf Storm and then 2HKOs back (OHKO with a high roll after LO recoil)
252 SpA Life Orb Serperior Leaf Storm vs. 248 HP / 192+ SpD Heatran: 35-40 (9 - 10.3%) -- possibly the worst move ever
+2 252 SpA Life Orb Serperior Leaf Storm vs. 248 HP / 192+ SpD Heatran: 69-82 (17.9 - 21.2%) -- possible 7HKO after Leftovers recovery
+4 252 SpA Life Orb Serperior Leaf Storm vs. 248 HP / 192+ SpD Heatran: 104-122 (27 - 31.6%) -- 31.5% chance to 4HKO after Leftovers recovery
wich sums up to 208-244 (54 - 63.2%) if heatran gets a low roll that allows Serperior to hit three times
0 SpA Heatran Lava Plume vs. 0 HP / 4 SpD Serperior: 224-266 (76.9 - 91.4%) -- guaranteed 2HKO