[Stingy Jack]

Sounds to me like you have been a victim of the classic "Cereal Bag Air Leak". Your cereal does that when it is exposed to too much air for a certain amount of time. There are ways you can battle this, however, so don't despair! I usually opt for the simple "roll up the bag" method. It is easy and effective. When you pour yourself a bowl, simply roll the opened part of the bag over itself several times until it is tight against the remaining cereal. If you think this is a hassle (which it can be ... after a while the crumpled bag hinders proper cereal pourage), simply purchase a $3.00 plastic container specially designed for cereal. Pour the cereal in this container and toss the box. The container will keep your cereal fresh until the last bite.