donphan
252+ Atk Stakataka Gyro Ball (150 BP) vs. 0 HP / 4 Def Machamp: 324-382 (100.9 - 119%) -- guaranteed OHKO
252+ Atk Choice Band Iron Fist Pangoro Hammer Arm vs. 0 HP / 4 Def Machamp: 373-441 (116.1 - 137.3%) -- guaranteed OHKO
Can someone please explain why either of these would ever need Zen Headbutt to lure Machamp? Or why Machamp would ever try to tank a hit from either?