8. Captain America Proves He's The Real Deal - Secret Empire #10 (2017)
When Steve Rogers was aged into a 90-year-old man, it looked like he would have to retire as Captain America for good. Luckily, he reverted to his regular form after coming into contact with the Cosmic Cube.
Little did Cap know that the Cube had been manipulated by Hydra, transforming Rogers into an agent of evil. His brainwashing was so absolute, his allies suspected Cap had been a Hydra agent from the very beginning.
Eventually, the real Steve Rogers broke free from the Cube's manipulations, causing Captain America to split into two. Although Steve could wipe the floor with his evil ersatz, he knew that wasn't enough. To prove he had never turned his back on his country, Rogers had to do something drastic.
While battling each other, Rogers allowed his Hydra counterpart to pick up Thor's hammer, Mjolnir. No matter how hard he tried, Hydra Cap couldn't budge the enchanted mallet, irrefutably proving he was not the real deal. Effortlessly lifting Mjolnir, Rogers smashed his doppelgänger in the face, showcasing to the world that he was the one and only Captain America.