Extreme foods are nothing new. Remember KFC's Double Down of 2010? But this year restaurant chains took the concept to a new level. "We've seen operators from different segments roll out buzzworthy food mash-ups that shock and delight curious customers," says Laura McGuire of food research firm Technomic. Case in point: the cronut (see above)—a doughnut/croissant hybrid. Whether these items left you drooling or repulsed, extreme food items keep restaurant concepts top of mind by generating news. We took a look at seven of them from the past year.