Obstagoon

While STAB Facade and Knock Off along with Guts make Obstagoon seem like an appealing choice, it holds no real niche. It is completely outclassed as a Guts user by Conkeldurr, which has much higher Attack, ability to cover nearly the entire metagame in four moveslots, STAB Fighting-type attacks to nail Cobalion — which Obstagoon can't touch — and priority in Mach Punch. Moreover, its middling Speed leaves it outsped by many common foes like Keldeo, Azelf, and Zarude. Even with Rest, Obstagoon is worn down way too quickly from entry hazards, sand damage, its weakness to U-turn, and its own Flame Orb to make use of its increased longevity.