Well, it looks like we might have an answer to that question in the form of late-1990s character Nels Van Adder, an early test subject for one of Norman Osborn's projects who mutated into a creature called "Proto-Goblin." The character's one and only appearance can be found in 1997's "Peter Parker, Spider-Man" #1, in a story written by Howard Mackie and titled "The Macabre Mystery Of The Proto-Goblin."

If this is indeed the character Khan will play in the film, it sheds some light on a few potential elements of the plot and timeline for the as-yet-untitled 2012 reboot of the "Spider-Man" movie franchise. [POTENTIAL SPOILER ALERT]

In the Marvel Comics Universe, Van Adder began as a research assistant to Mendel Stromm (a scientist who later becomes the mechanized villain Robot Master) and later volunteers to be a test subject for a new chemical developed by Stromm and Norman Osborn. The chemical would later provide the basis for the serum that transforms Osborn into the Green Goblin, though in this early form it caused Van Adder to transform into a monstrous, violent creature.

The story also features a prominent role for Captain George Stacy (played by Denis Leary in the film), the father of Gwen Stacy (Emma Stone).

If Khan is indeed playing a big-screen iteration of Van Adder, it stands to reason that Norman Osborn might factor into the mix, too — leaving the door wide open for Green Goblin to enter this new, rebooted Spider-Man franchise.

Of course, there's still no official word on the identity of the other villain in the film played by Rhys Ifans, despite popular rumors attaching him to the role of Dr. Curt Connors, a scientist who later becomes The Lizard. How Connors would fit into the story — or if Ifans could be playing someone else entirely, like Osborn or Stromm — remains the stuff of speculation at this point.

So what do you think?

(Many thanks to Marvel Universe Appendix and ComicVine.com for additional info on Proto-Goblin.)

Is Khan playing Proto-Goblin? How do you think Ifans' villain will fit into the mix? Let us know in the comment section or on Twitter! You can also follow me, Splash Page editor Rick Marshall, on Twitter!