Cloyster

Cloyster is one of the most terrifying, yet predictable, setup sweepers in the metagame, without the need to take up a Mega slot. Its colossal Defense stat, which rivals that of Mega Slowbro, along with its good offensive typing means Cloyster can set up on many physical attackers commonly seen in Battle Spot such as Garchomp, Landorus-T, and Dragonite. Thanks to its ability, Skill Link, Icicle Spear becomes a reliable multi-hit STAB move that allows Cloyster to easily break through Focus Sash and Substitutes. Furthermore, having access to a priority STAB attack in Ice Shard makes Cloyster rather difficult to revenge kill once it sets up and differentiates it from other common Shell Smash users such as Gorebyss and Barbaracle. However, Cloyster desperately needs a boost to become threatening, as both its Attack and Speed are below average prior to Shell Smash. Cloyster cannot afford to take any status such as a burn, which severely cripples it, and, given its abysmal HP and Special Defense stats, even resisted attacks like Scald can prove to be fatal.