Omastar

Omastar is one of the most solid Pokemon to use on rain teams because it can aid other sweepers, such as Kingdra and Kabutops. On top of that, its immediate power causes it to force the opposition either to sack a Pokemon or to have one of their walls take massive damage, and in most scenarios, Hydro Pump will easily 2HKO whatever Omastar is facing. Omastar also checks Talonflame and Mega Pinsir, giving it a niche unique to only itself and Kabutops. However, Omastar is outpaced by common Choice Scarf users such as Landorus-T and Keldeo and is very reliant on rain to do its job. It also compounds rain teams' Thundurus weakness, meaning it has to be played carefully. Omastar also faces competition from Kabutops because of their similar typings, so having both on the same team is unfavorable in most scenarios.