Popsugar Living Marshmallows Mega Stuf Oreo O's Cereal Cookies For Breakfast, Anyone? Oreo O's Cereal Is Now Mega Stuffed With Marshmallows! 29 May 2019 by Chanel Vargas View On One Page Photo 1 of 3 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 1 Previous Next Start Slideshow MarshmallowsWalmartOREOGrocery ShoppingFood TrendsFood NewsCookiesCereal