Granted. This new addition makes the cereal so popular that absolutely everyone in the world eats it every day for breakfast(WITH SYRUP?), and every other advertisement be it a billboard or a TV commercial is advertising it. Eventually, it becomes so popular that everyone chokes on the full-size marshmallows in their greedy attempt to eat them at the same rate they did the mini ones, and everyone but you dies. You are forced to live the rest of your life eating nothing but the immense amount of Lucky Charms that were produced prior to your death, and constantly live with the remainders of this horrible thing you've done all around. On top of that, the batch of Lucky Charms that came right after the last one that hit the stores contained the cure for death. This having not been announced, you accidently eat this cereal when you go to the factories, and are you immortal.
I wish for a delicious cake that is not poisoned or anything.