Toxicroak @ Black Sludge
Ability: Dry Skin
EVs: 244 HP / 96 Def / 28 SpD / 140 Spe
Impish Nature
- Bulk Up
- Drain Punch
- Ice Punch
- Taunt
Toxicroak is immune to Keldeo´s water STABS and takes its coverage moves fairly well:
252 SpA Choice Specs Keldeo Secret Sword vs. 244 HP / 96+ Def Toxicroak: 117-138 (31.7 - 37.5%) -- possible 5HKO after Dry Skin recovery and Black Sludge recovery
252 SpA Choice Specs Keldeo Hidden Power Ghost vs. 244 HP / 28 SpD Toxicroak: 155-183 (42.1 - 49.7%) -- 53.1% chance to 3HKO after Dry Skin recovery and Black Sludge recovery
252 SpA Choice Specs Keldeo Icy Wind vs. 244 HP / 28 SpD Toxicroak: 122-144 (33.1 - 39.1%) -- 0% chance to 4HKO after Dry Skin recovery and Black Sludge recovery
Add in that it recovers an absurd 24% HP per turn in rain and even more through Drain Punch attacks, and it´s very difficult for Toxicroak to lose this battle 1 vs. 1. Bulk Up gives Toxicroak a way to fight off Calm Mind versions of Keldeo (which could be difficult to differentiate from Specs Keldeo when it switches in for the first time), as well as Swords Dance Breloom and Terrakion, and gives it a way of beating Tentacruel instead of merely sitting endlessly on it. +1 Toxicroak also beats defensive Gliscor (not its peers Landorus-Therian, Garchomp and Excadrill, though) in two rounds after Bulk Up with Ice Punch. Taunt allows Toxicroak to beat Encore Politoed, Jellicent and Rotom-Wash (as well as Sub-Tect Tentacruel) as long as the rainy weather is preserved, though if one wants to cripple them and Gastrodon on the switch, Toxic can be used instead. Speed EV´s allow it to outspeed adamant Breloom and timid Jellicent. One can go up to 216 Spe for adamant Mamoswine, but even at +1, Toxicroak gets beaten.
Please note that Toxicroak is a relatively poor team player difficult to fit on synergistic rain teams. However, it does counter Keldeo well.