Gastrodon @ Leftovers
Ability: Storm Drain
EVs: 252 HP / 252 Spa / 4 Def
Bold Nature
- Scald
- Toxic
- Earth Power
- Recover
Gastrodon is pretty much a Seismitoad, except Gastrodon's ability to be immune to Water STAB, Storm Drain, boosts Gastrodon's Special Attack, and since Gastrodon resists Rock and Ground, Gastrodon can come in on any of Kabutops' attacks [with an extra chance to boost its special attack upon coming in], and with Toxic, and Reliable Recovery, and the chance to burn with Scald, Gastrodon can't really counter Kabutops because of +2 Stone edge 2HKOing, but it's a Hard Check nonetheless.
EDIT: Calcs
252 SpA Gastrodon Earth Power vs. 0 HP / 4 SpD Kabutops: 308-366 (118 - 140.2%) -- guaranteed OHKO
252 SpA Gastrodon Scald vs. 0 HP / 4 SpD Kabutops: 138-163 (52.8 - 62.4%) -- guaranteed 2HKO
Not Calcing Aqua Jet or Waterfall because of Storm drain.
252+ Atk Life Orb Kabutops Stone Edge vs. 252 HP / 4+ Def Gastrodon: 133-156 (31.2 - 36.6%) -- guaranteed 4HKO after Leftovers recovery
+2 252+ Atk Life Orb Kabutops Stone Edge vs. 252 HP / 4+ Def Gastrodon: 265-312 (62.2 - 73.2%) -- guaranteed 2HKO after Leftovers recovery