Image from Mosdo - click this image to see a larger one with more detail.
I'm a fan of balancing things out when I eat, but some people really like to stay with the same theme. For me, if I have pizza, I want to have a salad on the side as a way of balancing the nutrition. I don't like to have, say, fried cheese sticks. Cheese plus cheese is not my thing. I'm not criticizing those who enjoy such pairings, but, simply saying that they are not for me.
If you are someone who likes to layer on the fatty food all together, then the happy marriage of Mos Burger and Mister Donut has something you might like. For a 2,500 yen (about $25), you can get 4 pieces of Mos chicken (breaded and deep-fired, onion rings and French fires plus 4 donuts and a couple of Mosdo mugs for your coffee. I suggest you make that coffee black and let that be the only thing you drink the next day after chowing down on this fat fest.