3. Molecule Man
The Molecule Man (Owen Reece) is a fantastic character and one who is incredibly underrated when it comes to his power level. He has the ability to mentally manipulate molecules, allowing for a variety of effects, such as the creation of force fields, energy beams and hyperspace portals, which doesn't sound like a particularly powerful set of abilities in the grand scheme of things but, rest assured, he's a cosmic level threat who can put those powers to use in some very dangerous ways - indeed, he is actually one of the most powerful characters to have ever existed in Marvel comics. He gained his powers when he was bombarded with an unknown form of radiation. He named himself the "Molecule Man" and became a villain, taking vengeance on a world which had previously left him feeling bitter, anonymous and unloved. His power is such that he has been able to completely destroy objects as powerful as Thor's hammer Mjolnir, Captain America's vibranium shield, Iron Man's armour and the Silver Surfer's supposedly indestructible board (see picture above). He has also been able to regenerate his entire body, after it was destroyed, from the genetic imprint left by his fingers on his wand (a rod he used to focus his powers through). Essentially, he is incredibly powerful and nigh unkillable. That said, he hasn't always been a villain and his power has depleted somewhat following a retcon in the comics, but if he was to be introduced on screen as he was in the comics (which was in a Fantastic Four comic, incidentally), he'd undoubtedly be an enormous threat to the superhero group and the very universe in which they reside.