Moves
Foul Play avoids passivity against physical attackers, OHKOing +2 Kartana and dealing heavy damage to Swords Dance Primal Groudon. It can also hit some specially offensive targets for heavy damage, such as Lunala and Diancite Tapu Lele. The latter is severely chipped and even has a chance to be OHKOed after the Defense drops from its Mega Evolution. Roost provides reliable recovery; the loss of the Flying type is hardly ever detrimental, as Ground-type attackers are usually faster than Mandibuzz and thus cannot take advantage of it. U-turn grants Mandibuzz the ability to perform as a slow pivot that can’t be restrained by a Ground-type switch-in, giving it the edge over Volt Switch users in generating momentum. Defog is run as an entry hazard countermeasure. Toxic could work as a means to pressure offensive Mandibuzz switch-ins as well as Arceus formes if the team already has another Defogger. However, extreme care should be taken in using this move to avoid it being bounced back by an opposing Magic Bounce user.
Set Details
248 HP EVs combined with 252 Special Defense EVs turn Mandibuzz into a sturdy special wall, maximizing its ability to take special attacks like Overheat from Primal Groudon and Moonblast from Lunala. The HP EVs maximize the number of times Mandibuzz can switch into Stealth Rock. A Sassy nature and 0 Speed IVs give Mandibuzz its slowest possible U-Turn, letting a teammate switch in more safely. Big Pecks is run to avoid the occasional Defense drop from moves like Golisopod's Liquidation. An alternative set with a spread of 248 HP / 100 Def / 160 SpD and a Relaxed nature can also be run as a way to better check physical attackers like Kartana and Stone Edge Primal Groudon. The drop in special bulk does, however, cause Mandibuzz to be 2HKOed by +1 Moonblast from Lunala.
Usage Tips
Mega Evolving Mandibuzz early is important to increase its overall bulk, gain Magic Bounce to block status moves, and properly avoid opposing entry hazards. Foul Play should be used as the primary offensive move. It heavily pressures Lunala, Ho-Oh, most Diancite users, and relevant Necrozma formes. Additionally, it deals significant damage to physical attackers on the switch, as long as they don’t resist the move. Foul Play can also be used to punish foes that boosted their Attack, like Shift Gear Pinsirite Magearna, Swords Dance Metagrossite Kartana, and Swords Dance Primal Groudon. However, the damage received by a boosted physical move from these threats will invalidate Mandibuzz's ability to properly check other breakers. Thus, it is imperative to understand which Pokemon among the aforementioned poses the biggest threat to the rest of the team in order to choose which wallbreaker Mandibuzz ought to check. If a non-Mega Evolved Terrakion is found on the opposing team, it is important to be wary of using Foul Play, as it has very few switch-ins after a Justified boost. U-turn should be used as a means to punish predicted switches and generate momentum. It can also be utilized against passive foes to gain a free switch for a wallbreaker. However, switching is preferred to using U-turn if the opponent has the potential to deal heavy damage to Mandibuzz in a situation where the latter’s health should be preserved, such as against Altarianite users, Terrakion, and Zeraora. Roost should be used copiously to keep Mandibuzz healthy throughout the game and allow it to consistently check opposing threats. However, Roost may give threatening Pokemon like Nasty Plot Darkrai a free setup turn. In such cases, the recovery may have to be delayed in favor of U-turn. In situations where Mandibuzz is weakened while claiming momentum with U-turn, finding an opportunity to get it back in on a predicted switch to a Pokemon that doesn't pressure it can let it safely use Roost. Defog is to be used according to the entry hazard matchup on both sides. Beware, however, that if Mandibuzz is the only Defogger on the team, switching out without clearing Stealth Rock may deprive it of a quarter of its HP.
Team Options
Primal Groudon is a good partner for Mandibuzz, as it can switch in on Fairy-types like Magearna, Xerneas, and Altarianite Entei as well as Primal Kyogre and Zeraora, all of which pressure Mandibuzz. In exchange, Mandibuzz can take on Lunala and Darkrai as well as serve as a pivot against Arceus-Ground and Manectite Mew, thus taking pressure off Primal Groudon. Manectite Mew forms a functional defensive core with Mandibuzz, as it covers three of the most dangerous threats to it in Altarianite Zygarde, Altarianite Entei, and Terrakion. Alternatively, Aggronite Mew worsens the Entei and Terrakion matchup but does a better job at checking Pinsirite users like Magearna and Kartana, which heavily threaten Mandibuzz. It returns the favor by checking Lunala and Darkrai, both of which otherwise dismantle Mew. Will-O-Wisp Arceus-Ground has good synergy with Mandibuzz, checking the most prominent Altarianite users in the tier in Zygarde and Entei, while the latter is able to check Kartana and Lunala. Terrakion punishes other Sablenite users like Blissey and Zapdos, against which Mandibuzz is relatively powerless. In addition, Terrakion really capitalizes on the free switches Mandibuzz provides it with, as it is otherwise very difficult to bring it safely on the field. Still, it should be noted that both Pokemon are particularly weak to Fairy-types like Altarianite users and Arceus-Fairy. Altarianite Entei works as an offensive check to Altarianite Zygarde and Terrakion and is able to punish boosted Darkrai. Mandibuzz synergizes well with it, with its Ground immunity allowing it to take on Primal Groudon, a Pokemon that greatly hinders Entei, and the ability to help it switch in freely. Arceus-Fairy is another solid check to both Altarianite Zygarde and non-Pinsirite Terrakion, and in return appreciates Mandibuzz checking Lunala, Necrozma-DM, and Kartana to an extent. However, both are noticeably weak to non-Pinsirite Magearna variants. Finally, Kartana pairs well with Mandibuzz, as it takes advantage of Altarianite Zygarde and Arceus-Fairy. In return, Mandibuzz provides extra opportunities for Kartana to come in safely and break down teams with its slow U-turn.