We're talking OU here...
Checks and counters:
"There aren't any! The closest thing to a concrete counter now is
Chansey, but even then it's easily 2HKOed by Superpower with some prior damage (a common reality when you consider that Chansey doesn't use Leftovers). Nothing else can touch
Hydreigon on a good day.
Tyranitar is always OHKOed by Superpower, and
Ferrothorn and
Jirachi are scorched by Fire Blast.
Heatran is OHKOed by Earthquake and it takes a ton of damage from Superpower and everything else is at best 2HKOed by Draco Meteor. Fortunately, Hydreigon is fairly easy to check in the current BW metagame. The omnipresent
Genesect is quite simply the best Hydreigon check in the tier and a common obstacle for Hydreigon users.
Genesect can either hit it with a powerful Ice Beam or U-turn to simultaneously threaten Hydreigon and its teammates while also gaining momentum in the process.
Tornadus-T,
Breloom, and
Keldeo are common and every single one of them can destroy Hydreigon with their powerful Fighting-type moves. The ever-popular
Terrakion exists at every corner, waiting to turn Hydreigon into a liability since it is forced to switch out from its powerful Close Combats. It's also naturally outsped and KOed by
Latios and
Latias. Outside of fast offensive checks, you can rely on good old fashioned priority to take it down. Breloom,
Mamoswine and
Scizor are decent choices, though they should only bother trying to take on Hydreigon
when it has been weakened as Hydreigon's 92 / 90 physical defense is nothing to sneeze at."
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