I personally have used Mandibuzz as a physical wall in RU, rather than a special one. This is because two of its three weaknesses are primarily found in the form of special moves. It has been successful at handling all but the strongest physical moves in the tier repeatedly, largely in part due to Roost letting it heal itself and compensate for the Stealth Rock weakness. The removal of Hail is another gift for it since it doesn't have to worry about facing Blizzspam. One other move Molk did not mention that I love using on Mandibuzz is Knock Off. It removes Leftovers from Pokemon such as Steelix, and removes Choice items from Druddigon and Golurk, among others. Along with removing the advantage of the item, it helps to reveal what set a Pokemon might be using. For instance, Slowking often uses defensive sets with Leftovers or offensive sets with Choice Specs/Life Orb, so now you have a better idea of how to deal with such versatile Pokemon. As a result I sometimes run Knock Off/Toxic/Roost/Whirlwind (remember Knock Off ignores Taunt). My favorite defensive partner for Mandibuzz is Amoonguss since both Pokemon have reliable recovery. In addition, Mandibuzz can come in on Psychic moves for Amoonguss, and Amoonguss can come in on Electric-type moves for Mandibuzz. In particular, Amoonguss completely walls Rotom-C for Mandibuzz as long as it does not get Tricked a Choice item, and even then not all Rotom-C use Choice items. Since Mandibuzz is fairly slow (it's a wall...), Amoonguss's Stun Spore support is helpful. Plus who doesn't love 100% accurate sleep moves?!