Barujiina (apparently Mandibuzz is the English name) is the most effective 5th gen pokemon I have ever used. It's a huge pain to take down on its own due to Dustproof, Roost and defense on par with skarmory and special defense of half a blissey. I used it on stall team to great success.
Barujiina @Leftovers
172hp/212def/124 sp.def
-Roost
-Toxic
-Fly
-Whirlwind/Mean Look
Roost is an obvious choice. Toxic is a nice addition for any kind of wall, since it doesn't have too much offensive power. Fly is kind of an odd choice, but it works amazingly well. Not only is it great synergy with Toxic, allowing for maximum damage, it also keeps a number of offensive threats from rampaging through with their frail defense intact. It can hit Blaziken for a 2HKO, hit Breloom for 1HKO, any other fighting types and and the STAB + 90 base power is not too shabby when combined with toxic. The last slot adds a lot of versatility to Barujiina. Mean look is great for trapping walls and proceed to kill it with the toxic fly combo, or it can be used to take out offensive threats that Barujiina can handle. Whirlwind is a great life saver in case anything pulls off a sword dance or stat boost, just whirlwind it away while barujiina will most likely survive, barely (at least in my experiences with it, I've always managed to use him as a last ditch saver and then somehow heal it back to good health later). Knock off is also a great option for the last slot.
I've had a ton of fun with this bird and I hope you'll try it out as well.