Omastar

Omastar's vast movepool, high Special Attack, and access to Shell Smash make it a threatening setup sweeper able to muscle through common special walls like Cryogonal and Audino and Water-type checks such as Lanturn and Jellicent depending on its Z-Crystal. Its decently high Defense and typing give it plenty of setup opportunities against threats like Silvally-Fairy, Alolan Sandslash, and Skuntank. This allows it to take full advantage of its ability Weak Armor, which allows it to outspeed common revenge killers such as Choice Scarf Primeape. Omastar's typing also allows it to force out defensive Pokemon like Regirock, giving it more setup opportunities. Moreover, its access to both Spikes and Stealth Rock makes it a potent lead on more offensive teams, which is further enhanced by its ability to threaten most Defoggers and spinners such as Lurantis, Articuno, and Cryogonal depending on what it decides to run. However, Omastar's typing grants it weaknesses to common typings like Fighting, Ground, and Grass, which, when combined with its atrocious special bulk, give it a harder time setting up and make it easy to revenge kill with moves like Mach Punch. Due to its poor Speed, it remains slower than Choice Scarf users like Primeape even after a Shell Smash, meaning it often can be reliant on triggering Weak Armor and left easier to pick off with a priority move like Sucker Punch. Omastar's Speed also hinders its job as a lead, as most Defoggers and spinners outspeed it and threaten it if it isn't running the right coverage. Lastly, Omastar suffers from competition with Carracosta and Ludicolo as sweepers, with the former carrying Aqua Jet and having better bulk, making it harder to revenge kill, and the latter having a superior Speed tier, typing, and movepool. As a lead, Lycanroc is considerably faster and has access to Taunt and Endeavor, while Qwilfish is also faster and has a superior typing along with Intimidate.