Munchlax

Munchlax has a sky-high HP stat and a terrific Special Defense stat, which make it one of the best special walls in the metagame. Its ability Thick Fat allows it to better counter Ice- and Fire-type attackers, and its good Attack stat gives it the ability to hit hard and avoid becoming setup bait while performing its defensive duties. However, Munchlax performs far worse as a special tank in practice than it does on paper. Its low Defense stat means that Munchlax will often be forced out or taken out by physical attacks. The prevalence of Knock Off, including among the special attackers of the metagame, means that too often, Munchlax will lose its item and become crippled in its defensive capabilities early on. Furthermore, Munchlax lacks access to recovery outside of Rest and Berry Juice + Recycle, which leaves it prone to getting worn down throughout a match. Lastly, Munchlax's typing is not ideal for a defensive Pokemon in Little Cup, leaving it with a weakness to the common Fighting-type attacks.