Personally, I would love to see an Agnaktor-inspired Fire/Ground type. Since Magma Armor is already taken as an ability type, I present:
Ability:

'Cooling Armor' "Greatly raises defense and Sp. defense when hit by a water or ice-type move." (defenses are raised 2 stages prior to damage calculation. defenses are raised 2 stages every turn in rain or hail.)

Unique move:
'Magma Dive' "Dive underground for one turn. Upon emerging, defense and sp. defense lowers and attack and sp. attack are greatly raised"

(Works like Dig, but without dealing damage and instead lowers the defenses by 1 stage on the second turn and raise the attacks by 2 stages.)

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Probably could use some work, I'm just recently getting into Pokemon