Cloyster

Cloyster is a unique, solid setup sweeper with Shell Smash + Skill Link on hyper offense teams. Its naturally high Defense lets it set up on physical attackers such as Zygarde-10%, Mamoswine, and Excadrill. After a Shell Smash boost, Cloyster can threaten many top UU threats such as Hippowdon, Salamence, and Amoonguss, with only a select few Pokemon able to revenge kill it at +2. However, Cloyster's lackluster Special Defense stat and initial speed prevent it from setting up against offensive teams with powerful special attackers such as Azelf, Nihilego, and Thundurus-T. Even at +2 Speed, Cloyster is outsped by common Choice Scarf users such as Zarude and Hydreigon. Cloyster cannot fit coverage for both Slowking and Primarina, and it just cannot get past checks such as Keldeo, Rotom-W, and Tentacruel. It is vulnerable to priority moves such as Lycranroc-D's Accelerock and Conkeldurr's Mach Punch, and can have its sweep cut short by status, Life Orb recoil, and entry hazards.