Six Wings, Three Head, One full team sweep
- Flamethrower
- Surf/Dark Pulse
- Earth Power
- Draco Meteor
Ability: Levitate
Item: Expert Belt/Life Orb
Nature: Modest (+sp.atk -atk)/Timid (+spd -atk)
EV: 252 spd/252 sp.atk/4 def
This Hydra like Pokemon is honestky a terrifying sight. Earth Power allows this hydra to utterly destroy Heatran, which can tank Hydreigon if it was unequipped with a Surf. Expert Belt can be used over Life Orb for the unwanted HP loss, and since Hydreigon has such an amazing movepool, it can score a big dent at a x4 or x2 hit. Flamethrower allows Hydreigon to toast Ferrothorn, Genesect and Scizor. Combined with Life Orb or Expert Belt, it can strike a 1 hit to 2 hit ko. Surf is here for coverage but Dark Pulse is for STAB mainly. Draco Meteor can be used as a "last resort", but it can still tear through flesh. Max speed is to strike first and sp.atk is for maximum damage. Meanwhile, Modest is to put a bigger hole while Timid can be ran to outrun more stuff.
Other Options
Fire Blast, Heat Wave, Charge Beam, Focus Blast, Hyper Voice, Tri Attack, Thunder Wave, Toxic, Outrage, HP (Grass)
Counter
On a special set, anything that ends with a "sey" utterly walls this hydra to no end. Gastrodon can be a good counter if Hydreigon does not carry HP Grass. Breloom can be a decent counter as well, soaking up grass and water type moves with ease but it has to watch out for Flamethrower. Hydreigon has such a big movepool that it's not even funny. Countering is no where close to easy. An Adamant Mamoswine can possibly 2h ko it, but it must survive the second hit before ending this hydra's reign of horror