Of the many creations of Marvel that didn't exactly hit a high note for me, I'd have to count among their number the Adaptoid, a product of A.I.M. that was able to imprint on itself the likeness and abilities of a super-being and thus fulfill any number of covert operations on behalf of its masters. In its raw form, it resembled a featureless, walking blank slate which first infiltrated Avengers Mansion and took the form of Captain America after giving the real Cap a sedative in order to proceed with its "trace" of him. Its mission was to then eliminate Cap and go on to attack S.H.I.E.L.D.; but before it could proceed, the villain known as the Tumbler crashed in to attack Cap, not realizing the Adaptoid had taken the Avenger's place. Surprisingly, the Tumbler made mincemeat of the Cap-Adaptoid, and figured his rep would be made with this kind of victory--until the real Cap awoke and cleaned his clock.
The Adaptoid, now returned to its original state, was carted off to the lab, where Cap is joined by the rest of the Avengers in order to be briefed on it and investigate it further. Now, if you have in your custody a construct that calls itself "the Adaptoid," and you've seen first-hand what it's capable of--and you're not sure whether it's still operational--what's the worst thing you could do in its presence? That's right: expose it to four Avengers and practically hand it the means to adapt their powers and form itself into a new, more powerful enemy.
The most valuable addition to its power set would of course be Goliath. What are the Wasp or Hawkeye going to do for it? Goliath's trace would already have provided it with the power to shrink or grow; and it would need a quiver of custom-made, specialized arrows to augment the skill of Hawkeye's marksmanship. Nevertheless, once the other Avengers leave on (what else?) "Avengers business," Cap remains behind to guard their guest--and in short order, we're presented with a new Marvel foe that offers greater cover value than the less distinguishable Adaptoid.
Yes, the Super-Adaptoid, which has received one heck of a makeover and now resembles an amalgam of all four of the Avengers it's imprinted on itself--none of which were green, by the way. But given its startling new features we shouldn't quibble about nonessentials. So what do we have here? Well, let's start with what this thing must now hoist around and still have its hands free to engage in battle: facsimiles of Cap's shield, Hawkeye's bow and quiver, and what appear to be metal wings to give it flight. Its powers have also been increased accordingly--not only does it retain Cap's agility, but it now has Hawkeye's weaponry, Goliath's strength, and the Wasp's... the Wasp's... well, we'll have to just go with flight for now. Perhaps it also has a keen fashion sense and a compulsion to flirt.
Since the Adaptoid had to take Cap's shield for itself the last time, it comes as news that it's now able to duplicate its own accessories, such as Hawkeye's arrows and bow as well as a new shield. It's a mystery how it's going to fight with Cap's agility and acrobatic skill with all of its gear getting in the way--but thanks to Cap's response, at least it won't have to worry about that huge bow anymore.
Cap gives the Super-Adaptoid the answer to its ultimatum you'd expect; but even Cap can't match a version of himself combined with the power of Goliath. The Super-Adaptoid still has its stock of arrows to use as hand-held weapons, but we've seen all we're going to see of Hawkeye in its behavior. Besides, it appears it's doing fine at overwhelming Cap and keeping him on the run with its other abilities.
Cap would survive his fall to Earth by a series of aerial maneuvers that let him avoid hitting solid ground. And while he didn't accomplish his mission, it's technically a mark in the win column for the Super-Adaptoid, though Stan Lee's story would have us think that Cap has triumphed just by surviving.
As for the Super-Adaptoid, it now appears that he's cut his strings to A.I.M. and can now become a villain in his own right. For now, though, he treats his new freedom and autonomy cautiously, and decides to lay low until he's certain his old masters have truly abandoned him.
The Super-Adaptoid doesn't yet realize it, but his days are numbered--though you can't say that Marvel doesn't invest the time in trying to make this villain work. The Avengers amalgam would go on to battle the X-Men, as well as taking on the entire Avengers team and then lying in wait for Iron Man (and doing pretty well against him, once more using his bow and arrows--weapons which somehow always manage to be effective against the Avenger). But soon after, the Super-Adaptoid would unwillingly find itself transformed into a completely different and horrifying form. And its new masters have a new name for it...