Porygon @ Eviolite
Level: 5
Ability: Download
EVs: 156 HP / 40 Def / 240 SpA / 40 Spe
Modest Nature
- Tri Attack
- Psychic
- Hidden Power Fighting
- Recover
0 SpA Chinchou Thunderbolt vs. 156 HP / 0 SpD Eviolite Porygon: 7-9 (28 - 36%) -- 1.1% chance to 3HKO
(7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 9)
0 SpA Chinchou Hydro Pump vs. 156 HP / 0 SpD Eviolite Porygon: 7-10 (28 - 40%) -- 98.9% chance to 3HKO
(7, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10)
240+ SpA Porygon Tri Attack vs. 76 HP / 148 SpD Chinchou: 12-15 (48 - 60%) -- 90.2% chance to 2HKO
+1 240+ SpA Porygon Tri Attack vs. 76 HP / 148 SpD Chinchou: 16-21 (64 - 84%) -- guaranteed 2HKO
0- Atk Porygon Confusion Damage vs. 156 HP / 40 Def Eviolite Porygon: 2-3 (8 - 12%) -- possible 9HKO
(2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3)
So let's do some math.
Thunderbolt does 7 damage almost every time, but has the chance of doing 9, and will not miss. Porygon with 156 EVs has 25 HP. If we're using Thunderbolt, then the only things that matter are 3 high rolls on thunderbolt (a 1.1% chance to happen, and this bypasses all confusion reliance) since 2 vs 3 damage makes no difference in a 7+7+7 situation or a 7+7+9 situation.
Porygon's Download is not a 100% chance vs a 14/14 Chinchou, it's only a 50% chance to happen. If it doesn't get the download boost, then it has an actual 73.062% chance to 2HKO due to a brightpowder miss. If it does get the download boost, it has an 81% chance to 2HKO due to a brightpowder miss.
Porygon switches in on a confuse ray.
I got this far then realized none of this is needed. Hydro Pump 3HKOs virtually all of the time, and Chinchou outspeeds. Not even taking Brightpowder or Porygon's chance to get an attack boost into account, that's an 80%^3 times a 98.9% chance. Overall? A 50.6368% chance for Chinchou to win.
This does not counter.