Doritos are the devil!
Wasn't it George Carlin who talked about there being some kind of time warp around cookies, so that when you open the box, you enter a fugue state as time bends around said cookies, and time only is restored once the cookies have been eating, leaving you with only an empty box and crumbs all over you. :)
Oreos are right up there too!
what takes the cake though? Dunkin Donuts Munchkins...since they're little balls of doughy goodness, and poppable...they are inherently evil.