DarkNostalgia
Fading in, fading out, on the edge of paradise
252 Atk Life Orb Bisharp Sucker Punch vs. 0 HP / 0 Def Hoopa: 251-296 (83.3 - 98.3%) -- guaranteed 2HKO
252 Atk Life Orb Bisharp Sucker Punch vs. 0 HP / 0- Def Hoopa: 278-329 (92.3 - 109.3%) -- 56.3% chance to OHKO
252+ Atk Life Orb Technician Breloom Mach Punch vs. 0 HP / 0- Def Hoopa: 235-278 (78 - 92.3%) -- 31.3% chance to OHKO after Stealth Rock
252+ Atk Life Orb Technician Breloom Mach Punch vs. 0 HP / 0 Def Hoopa: 212-251 (70.4 - 83.3%) -- guaranteed 2HKO after Stealth Rock
252 SpA Keldeo Secret Sword vs. 0 HP / 0- Def Hoopa: 234-276 (77.7 - 91.6%) -- 31.3% chance to OHKO after Stealth Rock
252 SpA Keldeo Secret Sword vs. 0 HP / 0 Def Hoopa: 210-247 (69.7 - 82%) -- guaranteed 2HKO after Stealth Rock
+1 0 Atk Talonflame Brave Bird vs. 0 HP / 0 Def Hoopa: 246-289 (81.7 - 96%) -- guaranteed 2HKO
+1 0 Atk Talonflame Brave Bird vs. 0 HP / 0- Def Hoopa: 273-322 (90.6 - 106.9%) -- 43.8% chance to OHKO
0 Atk Ferrothorn Gyro Ball (150 BP) vs. 0 HP / 0 Def Hoopa: 231-273 (76.7 - 90.6%) -- guaranteed 2HKO
0 Atk Ferrothorn Gyro Ball (150 BP) vs. 0 HP / 0- Def Hoopa: 258-304 (85.7 - 100.9%) -- 6.3% chance to OHKO
0 Atk Ferrothorn Gyro Ball (150 BP) vs. 0 HP / 0- Def Hoopa: 258-304 (85.7 - 100.9%) -- 87.5% chance to OHKO after Stealth Rock
252 Atk Life Orb Weavile Icicle Crash vs. 0 HP / 0 Def Hoopa: 259-305 (86 - 101.3%) -- 12.5% chance to OHKO
252 Atk Life Orb Weavile Icicle Crash vs. 0 HP / 0- Def Hoopa: 286-339 (95 - 112.6%) -- 68.8% chance to OHKO
252 Atk Life Orb Bisharp Sucker Punch vs. 0 HP / 0- Def Hoopa: 278-329 (92.3 - 109.3%) -- 56.3% chance to OHKO
252+ Atk Life Orb Technician Breloom Mach Punch vs. 0 HP / 0- Def Hoopa: 235-278 (78 - 92.3%) -- 31.3% chance to OHKO after Stealth Rock
252+ Atk Life Orb Technician Breloom Mach Punch vs. 0 HP / 0 Def Hoopa: 212-251 (70.4 - 83.3%) -- guaranteed 2HKO after Stealth Rock
252 SpA Keldeo Secret Sword vs. 0 HP / 0- Def Hoopa: 234-276 (77.7 - 91.6%) -- 31.3% chance to OHKO after Stealth Rock
252 SpA Keldeo Secret Sword vs. 0 HP / 0 Def Hoopa: 210-247 (69.7 - 82%) -- guaranteed 2HKO after Stealth Rock
+1 0 Atk Talonflame Brave Bird vs. 0 HP / 0 Def Hoopa: 246-289 (81.7 - 96%) -- guaranteed 2HKO
+1 0 Atk Talonflame Brave Bird vs. 0 HP / 0- Def Hoopa: 273-322 (90.6 - 106.9%) -- 43.8% chance to OHKO
0 Atk Ferrothorn Gyro Ball (150 BP) vs. 0 HP / 0 Def Hoopa: 231-273 (76.7 - 90.6%) -- guaranteed 2HKO
0 Atk Ferrothorn Gyro Ball (150 BP) vs. 0 HP / 0- Def Hoopa: 258-304 (85.7 - 100.9%) -- 6.3% chance to OHKO
0 Atk Ferrothorn Gyro Ball (150 BP) vs. 0 HP / 0- Def Hoopa: 258-304 (85.7 - 100.9%) -- 87.5% chance to OHKO after Stealth Rock
252 Atk Life Orb Weavile Icicle Crash vs. 0 HP / 0 Def Hoopa: 259-305 (86 - 101.3%) -- 12.5% chance to OHKO
252 Atk Life Orb Weavile Icicle Crash vs. 0 HP / 0- Def Hoopa: 286-339 (95 - 112.6%) -- 68.8% chance to OHKO
Sorry for the wall of calcs, but here are just some scenarios that Naive > Hasty benefits Hoopa-Unbound. Obviously you need to take into account prior damage but it's sort of like a safety net. Not saying that Naive should be used over Hasty, just saying that Naive is a viable option.