The Obama Factor... Waiting for Beyonce... Halloween Parties...

SCARE TACTICS: Fashion world denizens are regularly charged with being jaded, but considering the amount of fancy-dress party and special events celebrating Halloween, their behavior is more like a classroom full of giddy nine-year-olds. Earnest Sewn kicked things off by hosting a pumpkin carving last weekend at its Lower East Side location, complete with face painting and candy apples. Anya Hindmarch got involved (despite the brand’s Brit provenance) by hosting a weeklong trick-or-treat at all of its stores, with some lucky visitors winning a bag, clutch or purse from the new collection. Tonight, designer Jeremy Scott is hosting a party at nightclub Caine Luxe, while Mariah Carey is hosting a fete and simultaneously celebrating her six-month wedding anniversary to Nick Cannon over at Marquee. (Expect to see designer Brian Reyes among the guests). On Friday, the actual holiday, Donna Karan, André Leon Talley and Martha Stewart are joining Bette Midler for her Hulaween party at the Waldorf honoring Alice Waters (it’s a benefit for the New York Restoration Project in disguise). Michael Kors will be taking a break from judging “Project Runway” to hand out awards for best costume. Meanwhile, his TV co-star, Heidi Klum, will be downtown at 1Oak, hosting her annual Halloween extravaganza.