An alien named Omega who can perfectly predict your actions gives you two boxes, A and B. If Omega predicts you will open just A, it will put $1,000,000 in A. But if the alien predicts you will open both boxes, it will put $0 in A. Additionally, Omega will always put $1000 in box B.
You get to keep whatever money is in the box(es) you open. What do you do?