The Mizukage takes this for sure. In an actual battle, he doesn't tell Gaara that he fights with a genjutsu. Knowing that, Gaara I think wouldn't even destroy the clam, let alone deal with joki boy.
gaara countered joki boy by himself,mizukage refused to tell gaara the weakness of joki boy.last time i checked mizukage didnt hit gaara,he just managed to elude gaara's sand coffin with his oil,and didnt gaara catch him in like 30secs at the start and hold him for long enough to beat his dad?,gaara crushes minerals in the ground,you think he can't crush gold in the ground and use it?gaara used minerals to form shield of shukaku,he can do the same to his pyramid. It dosent take a genius to figure out that the clam is used for genjutsu after it releases the mist. Gaara found the clam alone,he could just have a sand clone destroy the clone or use a sand wave to crush it.besides,gaara fought an edo mizukage,he needed to catch,restrain and then seal him, which allowed him to break away,he isnt suigetsu who can turn instantly,if you watch closely,it seeps through slowly,then the sand breaks.it also takes chakra,he had unlimited stamina so he could do it indefinately,he can't do it here,and what weaknesses did he say anyway?wasnt it just abt the clam thing or did i miss something?. Gaara wins high diff. imo