Can't Have Your Cake and Eat it Too

One time, after I thwarted my Evil Twin brother's latest scheme to take over the world with an army of zombified lemurs, I told Kram through the bars of his cell that nothing would make me happier than if we could just get along for once. He replied that I couldn't have my cake and eat it, too. To prove him wrong, I went down to the nearest Ralph's, bought a Carvel ice cream cake, brought it back to his cell, and ate it in front of him. I guess some siblings will always be rivals.