>>30545992Just did the math by the way.
+1 212 SpA Porygon-Z Hidden Power Ground vs. 0 HP / 0 SpD Tapu Koko: 248-294 (88.2 - 104.6%) -- guaranteed OHKO after Stealth Rock (31% OHKO without SR)
Should also be guaranteed OHKO with 1 layer of Toxic Spikes or regular Spikes.
Going to 252 SpA doesn't change the breakpoints in any way.
Contrast:
+2 212 SpA Porygon-Z Thunderbolt vs. 0 HP / 0 SpD Tapu Koko: 124-146 (44.1 - 51.9%) -- guaranteed 2HKO after Stealth Rock (I used +2 here to emulate Electric Terrain, because it doesn't seem to boost anything in the simulator)
+1 212 SpA Porygon-Z Ice Beam vs. 0 HP / 0 SpD Tapu Koko: 187-220 (66.5 - 78.2%) -- guaranteed 2HKO after Stealth Rock
+1 212 SpA Porygon-Z Shadow Ball vs. 0 HP / 0 SpD Tapu Koko: 166-196 (59 - 69.7%) -- guaranteed 2HKO after Stealth Rock
HP Ground is better vs Salazzle than TBolt (OHKO vs 2HKO) but if there's sneaky pebbles they both OHKO
HP Ground 2HKOs 252HP Nihilego vs TBolt 4HKO, sneaky pebbles gives a 93% OHKO vs guaranteed 3HKO
A-Marowak at EVs: 248 HP / 16 Atk / 112 SpD / 132 Spe gets 1shot by Shadow Ball with SR, which Ice Beam and HP Ground can't do; without Aegislash around this is the best reason for Shadow Ball
Conclusions:
Run HP Ground and hazards if you want to kill Tapu Koko
Run HP Ground if you want to kill Salazzle without hazards
Run HP Ground if you're worried about Nihilego
Run Shadow Ball if you're worried about A-Marowak
Run Recover
if you're a bitch lol 
