Shedinja

Shedinja's unique ability in Wonder Guard allows it to potentially become a deadly late-game wincon, as it's able to completely wall threats such as Alolan Raichu and Hitmonchan lacking Stone Edge. However, being stuck with only 1 HP nullifies any sort of defensive utility Shedinja could have for itself and makes it instantly fall to the ubiquitous users of entry hazards, Toxic and Will-O-Wisp, Leech Seed, and Snow Warning. Wonder Guard also does nothing against common attacking types such as Rock, Flying, and Dark, as well as Pursuit from the likes of Skuntank and Stoutland. All of this means Shedinja requires strenuous team support to function, which ultimately makes it a liability for most teams. Furthermore, Shedinja faces severe competition with Scyther as a setup sweeper, which has superior stats across the board, reliable recovery, and the ability to pivot with U-turn.