>>25011716Not necessarily, we all know Giovanni is a dirty fucking cheater.
I'm guessing he used X Special to pump up his Rhydon before battle, and has some home field advantage fuckery going on that hampers enemy stats. If we assume +6 Ryhorn and a Jolteon with no investment in Special Def, and a field effect of -6 to all stats, we get:
+6 0+ SpA Rhyhorn Thunderbolt vs. -6 0 HP / 0 SpD Jolteon on a critical hit: 422-497 (155.7 - 183.3%) -- guaranteed OHKO
OHKOs are possible up to a -4 in this scenario. If we assume Jolteon has shit IVs, it goes up to -3 providing like a 75% chance to OHKO on crit.