The prefix "mega," which is Latin for incredibly, stupidly huge, gets a workout here being applied to something that simply can't be made mega. A "bite" is anything you can tear with your incisors and shove into the cavity of your mouth. That can't be mega no matter what level of competitive eater you are. What we have here is copy for copy's sake. "We can't just call it 'bite' ... what about 'giant' ... 'huge' ... uh, hey 'mega!'"
(N.B. I'll admit the photo doesn't do this poor cookie justice; this was one of those cookies that's the size of a pizza.)
(N.B. I'll admit the photo doesn't do this poor cookie justice; this was one of those cookies that's the size of a pizza.)