Marshadow

Marshadow separates itself from other common picks with reliable and hard-hitting STAB options with unresisted coverage. Its great Speed tier allows it to outpace Mega Rayquaza and Arceus, while its Fighting typing, immunity to Extreme Speed, and ability to steal stat boosts allow it to revenge kill Swords Dance Arceus formes and check some Calm Mind sweepers. A fantastic ability in Technician also enables it to boost the power of moves such as Rock Tomb, Shadow Sneak, Hidden Power Ice, and Pursuit, while a 195-Base Power STAB Z-Move allows it to break through bulky defenders, stall, and balance. Spectral Thief is an amazing STAB move, due to the prevalence of boosting moves in the metagame, that allows Marshadow to be a great weapon against hyper offense. Furthermore, a great priority move in Shadow Sneak helps Marshadow threaten faster Pokemon such as Ultra Necrozma and Mega Gengar, while Bulk Up allows it to be a frighteningly powerful wallbreaker after a boost. Marshadow also has the potential to serve as an excellent revenge killer against offensive teams with correct prediction, but it struggles to break defensive walls it can't hit super effectively. Marshadow also suffers from having poor defensive utility, meaning it can't switch into many of the Pokemon it checks, and is weak to common threats, such as Arceus-Fairy and Yveltal, both of which threaten it out with their respective STAB options. Because of its middling Attack stat, it can be walled by Pokemon such as Arceus-Poison, Primal Groudon, and Zygarde.