Kartana

Just like the rest of the Ultra Beasts, Kartana hails from a distant universe where balanced stats aren't a thing. Its flagship Choice Band set warps the match around its virtually unmatched immediate wallbreaking power, often forcing hard reads to limit progress. That raw power is supplemented by a superb natural Speed stat and well above-average physical bulk to give it significantly more entry opportunities than other wallbreakers and plenty of targets to revenge kill. If that wasn't enough, Kartana has Beast Boost to naturally punish sacrifices and efficiently clean games with a Choice Scarf. Its Swords Dance variant shapes the metagame’s Speed tiers, as there are very few defensive counters to all of its Z-Crystal options at once, requiring faster revenge killers as counterplay. Additionally, its physical bulk isn't just useful for switching directly into attacks; with access to Synthesis + Defog, Kartana is a strong Defog option on sun teams to counter Stealth Rock Garchomp and Landorus-T. While it looks perfect from the front, its bulk is as two-dimensional as the paper it's modeled on; Kartana has the worst special bulk of a fully evolved Pokemon not named Shedinja. Additionally, there's generally very little that's good about Grass as an offensive type due to the litany of common Grass-resistant Pokemon and unimpressive spread of super effective targets; Steel does little to help either, forcing Kartana to rely on its non-STAB moves. There are also plenty of set-dependent checks to Kartana, with options like Skarmory, Zapdos, Tornadus-T, and Mega Scizor answering several Kartana variants.