Omastar

Omastar is one of the most flexible Water-types in the tier, able to run both defensive and offensive sets successfully and fitting on both offensive and balanced team archetypes. Having access to Stealth Rock, Spikes, and Toxic Spikes means it can fulfil a team's need for entry hazard support entirely on its own, and its excellent Defense and Special Attack stats give it many switch in opportunities and a good matchup against many anti-hazard Pokemon, such as Kabutops, Pelipper, and Xatu that lack Grass Knot. Meanwhile, Shell Smash and Swift Swim make offensive sets extremely deadly and give Omastar pride of place as one of the best rain sweepers available, with its aforementioned Defense making it difficult to revenge kill with most priority attacks. However, its low initial Speed, Special Defense, and crippling 4x weakness to Grass-type attacks, alongside weaknesses to common Electric-, Fighting-, and Ground-type moves, make it fairly easy to force out when it does not have a Speed boost. This results in Omastar relying on strong team support to make the most of its defensive and offensive attributes outside of early-game. Furthermore, Omastar faces competition as a sweeper from Barbaracle and Kabutops, which have better Speed tiers and boast different coverage options.