Non Rain Mixdra. I had this bad boy purely to take on the above defensive Combo. Admittedly HP Fire is terrible in rain but the idea is purely that you can't out predicted all day by the above. It eventually will break what is a **very** common and potent defensive core.
Kingdra @ Lum Berry
Trait: Swift Swim
EVs: 176 Atk / 80 SAtk / 252 Spd
Naive Nature
- Waterfall
- Outrage
- Dragon Dance
- Hidden Power [Fire]
Absorbs status and gets you to +2 as the defensive core tries to stamp its authority. This works best with Spikes support as Ferrothorn will take more than just HP Fire to finish him off.
Test it, I'm not sure how worth a slot it is but it helps with a common Defensive core that alot of teams struggle to get through.
I'm currently using a similiar same set except for a different spread. I've found that Hidden Power Fire is a lackluster move for Kingdra. I've barely used it on Ferrothorn, and even though can 2HKO it with enough SpA, you'll likely get hit with Leech Seed, Thunder Wave, or Power Whip anyways.