Mega Moltres - Drought Mega Zapdos - Drizzle Mega Articuno - Snow Warning
even though i wouldnt use them (dont like to use non-evolvers/ or legendaries) i would 100% be behind this. shoulda been their hidden abilities. but mega forms that cause these weather hazzards, that be interesting.
what if in the process they also became /fairy or /dragon type? --- dandelion + flabebe + fairy wind = saddest moment in pokemon. 3ds fc. jd, 0602-6823-9646 or 0146.9112.0071
Magic Guard MegaMoltres with higher SpA/SpD/Spe would be interesting in OU. Would stop a lot of Sun abusers cold, check Scizor, Jirachi and Volcarona and still be useful in Rain with STAB Hurricane along with zero recoil LO.