Y'know, I was just thinking, if Mandibuzz is so bulky, why not just try her as a ridiculously bulky Nasty Plotter? I recognize that she only has 55 base SpA, but even so, she can still get a lot of boosts, and Roost off the damage pretty easily.
I'm not really sure what the EV spread would be, but it seems like she would would as a mono-attacker pretty well. She has Air Slash and Dark Pulse which she can pick from as STAB moves. She'd need Overcoat though. Don't try using her as an offensive sweeper with Breakable Armour, because then you just have a crappy Special Attacker with low defense that's still outsped by a whole crapload of stuff.
I was thinking something like:
Mandibuzz @Elemental Plate / Leftovers
EVs: 172 HP / 252 SpA / 84 SpD
Overcoat
Nature: Modest
- Substitute
- Nasty Plot
- Roost
- Dark Pulse / Air Slash
Substitute is mainly there so that she can avoid Toxic and be able to beat Seismic Toss Blissey. 172 HP gives 404 HP so that her Seismic Tosses won't break your Subs in one hit, and the Elemental Plate gives Dark Pulse just enough strength to 2HKO Blissey at +6, reaching 1096 SpA factoring in the plate. (You can essentially say that Mandibuzz has 274 SpA at +0 with the Plate on since she's a mono-attacker). It deals a max of 50%, and Blissey can't keep spamming Softboiled, because eventually Dark Pulse is going to flinch her, and she'll die. Unfortunately, her Ice Beams will break the Sub, but her Flamethrowers definitely won't, and it seems like Flamethrower's more common than Ice Beam on Blissey. It's always funny to see a special attacker with base 55 SpA beating Blissey one-on-one. Her Subs are pretty damn hard to break with other attacks too. Overcoat and Roost will more than compensate for the lack of Leftovers recover should you choose not to use them. 84 SpD would allow for equal defenses (or as equal as you're going to get). This set is of course more potent when there's Toxic Spikes on the field, so it can act as the regular SubRoost set, but with actual offense as well.
I imagine that this set does have some problems, but it's definitely a way for Mandibuzz to use both her bulkiness and Nasty Plot in one.