The Incredible Hulk #123

Mr. Fantastic uses a machine on the Hulk that turns him back into Bruce Banner and allows him to transform into the Hulk at will while still retaining his own intellect. Bruce vows never to become the Hulk again and reunites with Betty who accepts his proposal of marriage. Thunderbolt Ross also makes nice with his soon to be son-in-law but asks him to become the Hulk one last time to protect a new and deadly military weapon during transport. The Leader tries to steal the weapon but is stopped by the Hulk who finds himself feeling more savage as he almost kills his deadliest foe.