World War Hulk vs Ben 10
Now before I am assassinated for making a thread that has already been done before, let me clarrify.
WW Hulk is just WW Hulk, bloodlusted, morals off. He knows he is going to brawl, but he doesn't know who. Hulk gets 10 minutes of prep time.
Ben 10 has all his aliens he's ever had, excluding Alien X. He has the powers of every alien combined. He doesn't need to transfer aliens during the battle, because he has all the powers of all his aliens at one, including the Ultimate versions. In other words, Ultimate Ben. He too, gets 10 minutes of prep.