Gorebyss. It's higher offensive stats make Huntail struggle to give it competition, and the fact she focuses on Special rather than Physical gives it access to effective access to Hydro Pump as well as the Hidden Power coverage that Huntail can't use as well due to it's lower Special Attack; it has to resort to Waterfall for STAB. If you abuse Shell Smash, Gorebyss outclasses Huntail in everything it does well; go with Gorebyss.
