Deck above is Froslass(LA)/Ampharos(PT)
Counter is Toxicroak G/Skuntank G/Honchkrow G w/ Dialga G Lvl X tech and Crobat G tech
Strategy: Use Honchkrow G to gather Galactic HQs to ensure that evolved pokemon have damage on them. Then, use Honchkrow to snipe at Ampharos (or Flaafy, if you get that opportunity,) while stalling for time to set up Toxicroak G and Skuntank G. Then, move Toxicroak G to Active and Skuntank to Poison. Either set it up so that you unexpectedly 1-hit the Froslass, or use poison/Crobat's Power to KO it after Destiny Bond. Dialga G Level X allows Skuntank's power, if you let them keep/get Ampharos out after Honchkrow is gone.