Okay Ace, it sure wouldn't be nice to be hit by that Head Smash so use dig to avoid the attack, and then torment him a bit so he won't be using that Head Smash for a while. Finish it with a Heat Wave and hope you don't get poisoned.
Evasive Dig ~ Torment ~ Heat Wave
Using Torment as it's second effect:
Torment: The Pokemon imbues itself with dark energy and torments the foe, preventing the opponent from using using the same attack twice in a row or from using any moves used in the previous round for six (6) actions.
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