While Aerilate gives this monster some ball-bustingly powerful STAB with no drawbacks and fantastic offensive typing, that's not what really makes this thing broken. What does is its bulk, thanks to it's crazy physical defense (and decent sp.def) amplified by Intimidate when it's in its base form. This makes snagging dragon dances an absolute doddle, and you can't try and whittle its health down to revenge kill it with priority on the revenge kill either thanks to its access to Roost, and there's nothing apart from Weavile or Mamoswine that can use their priority to take this thing down when it's healthy. Even Prankster Priority status is unreliable because Mence often gets to set up a substitute ahead of time, can actually exploit burns by running Facade over Return, or can just flat out heal itself with Refresh. In the meantime it only needs one DD to outspeed all of the relevant metagame threats, and there's very little that can stand up to taking +1 Aerilate Returns and retaliate. Most of the few things that do get blown away by its other attacking options, which are as broad and effective as they come, with the right moves to smash everything that resists Flying, whether that's EQ, Fire Blast or just extremely powerful Dragon STAB. Long story short, thanks to the combination of its bulk, power and coverage, it usually only needs one free turn to set up and blow an entire enemy team clean out of the water, and these free turns are extremely easy for it to get. Your offensive checks are limited to Mamo and Weavile (barring ridiculous shit like Scarf Greninja,) and Mence can get past both of these with the right set and a timely Intimidate, and neither of them have a hope in hell of switching in safely. I guess it does have some counters in the shape of physically bulky Porygon2 and Cresselia, but even these need to have their health preserved if they want to switch in safely, and their value in the rest of the metagame is somewhat questionable, plus running these forces you into using a very specific, bulky-focused team archetype.



So yeah. If this doesn't warrant an instant ban then I'm not sure what does.