Other Options

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Toxic can be used over U-turn to cripple defensive Pokemon like Porygon2, Hippowdon, and Avalugg; however, Mandibuzz then misses out on U-turn, which is very much appreciated thanks to it being able to swing in momentum for free against a predicted switch-in. Taunt is also an option over U-turn to prevent walls like Toxapex, Blissey, and Celesteela from using status moves, helping Mandibuzz wear them down. Knock Off can be used over Foul Play to annoy walls like Toxapex, Porygon2, and Blissey, but without Foul Play, Mandibuzz cannot punish threatening setup sweepers like Azumarill and Mega Gallade.

Checks and Counters

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Fairy-types: Fairy-types like Mega Diancie, Tapu Lele, and Hatterene have little to no trouble beating Mandibuzz.

Status: As a defensive Pokemon that is intended to be used for longer games, Mandibuzz finds itself susceptible to statuses like Toxic poison and paralysis. Toxic puts it on a timer, while paralysis can prevent it from performing its role effectively.

Super Effective Attacks: Super effective attacks from Pokemon like Alolan Raichu, Terrakion, and Galarian Darmanitan can make Mandibuzz extremely weakened or even OHKO it.

Wallbreakers: Mandibuzz has trouble facing extremely powerful wallbreakers like Mega Heracross and Greninja, which can break it apart easily.

Stallbreakers: Common stallbreakers like Gliscor and Mew can completely shut down Mandibuzz with Taunt, cripple it with Toxic or Will-O-Wisp, and prevent it from recovering its health.

Walls: Mandibuzz struggles to get past certain walls on its own such as Toxapex, Amoonguss, and Zapdos, as even Taunt variants cannot stop them due to their massive bulk.