Altaria @ Altarianite
Ability: Natural Cure
EVs: 4 HP / 252 Atk / 252 Spe
Adamant Nature
- Dragon Dance
- Return/Frustration/Facade
- Earthquake
- Roost
or
Altaria @ Altarianite
Ability: Natural Cure
EVs: 248 HP / 136 Def / 96 SpD / 28 Spe
Impish Nature
- Dragon Dance
- Return
- Refresh/Heal Bell/Substitute
- Roost
Offensive or bulky Mega Altaria. I know it's usually relegated to second tier status below Mega Charizard X as a Dragon Dancer, but STAB Return (or whichever move you choose to use) after a Dragon Dance is nothing to laugh at. Earthquake is most notably for Heatran, Bisharp and Excadrill, although Scarf Excadrill can be annoying. Of course strong Bullet Punch users like Mega Metagross and Scizor are Altaria's biggest problems. Not 100% sure on the EVs and nature for this one.
Gengar @ Life Orb/Leftovers
Ability: Levitate
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
- Substitute/Taunt
- Shadow Ball
- Sludge Wave/Sludge Bomb
- Hidden Power [Fire]/Focus Blast
Gengar is really strong and can nuke some of Altaria's checks and counters with it's strong STABs. It can nuke all of the Fairy type switch ins with Sludge Wave/Bomb and Shadow Ball completes pretty solid neutral coverage for the tier. If it gets the change to get behind a sub it's even better. Hidden Power Fire is for Scizor, Skarmory and Ferrothorn.