Decidueye

Decidueye's fantastic STAB combo and offensive versatility make it a great wallbreaker in NU. Only a handful of Pokemon wall Decidueye's STAB attacks, and even fewer are fast enough that its teammates can't exploit them after U-turn uses or double switches. Furthermore, since Decidueye can use both physical and special sets to great success, finding defensive counterplay isn't so simple until you know its set. Despite these advantages, Decidueye isn't perfect, and its Speed is its most notable flaw. Even though its Shadow Sneak is strong when boosted, faster attackers like Talonflame and Drapion easily revenge kill it, with only the former being susceptible to Decidueye's priority attack. Decidueye also struggles in certain matchups, especially against Dark-types like Guzzlord, Scrafty, and Sneasel, since it's forced to use U-turn more often instead of wallbreak. Lastly, because there are so many great Grass-types in NU, Decidueye can sometimes be hard to justify using over other options.