How did the name "Kristy" come up? It's totally unintutitive, it has no "Flotzel" in the name anywhere. Even Tyraniboah has "Tyrani" in "Tyranitar".
Sassy Heatproof Bronzong could counter it, as could Careful Registeel with Ice Punch, possibly.Slice'n'dice...is it just me, or did you vote twice?
Anyway, I say MIXMENCE (the Life Orb, Brick Break, Crunch, Draco Meteor, Fire Blast variety) because there isn't a counter to it, literally. Everything in the metagame gets hit hard.
When a set has literally 0 counters, you know it is...