EVs: 4 HP/252 SAtk252 Spe
Item: Black Sludge
Gengar can switch in to anything Hariyama does, except for Ice Punch. If Hariyama didn't use Ice Punch on the switch, Gengar can set up a Sub as Hariyama switches out, or, for some reason, uses Ice Punch to break it. Gengar then uses Disable to disable Ice Punch, leaving Hariyama absolutely helpless against it, as Gengar is immune to Earthquake and Close Combat (why you'd use EQ alongside CC is beyond me, as both have redundant coverage).