Definitely Conan and The Thing, mainly because of the ease with which you can make it "happen".  I'd tell the story from Conan's point of view but without translating Ben's dialogue for the reader (I'd use generic alien squiggles in the word balloons).  Conan's in the process of graverobbing an ancient temple when Ben appears.  Of course a fight ensues with Ben more or less ignoring Conan so as not to harm him.  Then the big baddie appears, and he conjurs up enough shock troops to slow even the Thing down, and the two battle it out side-by-side (perhaps Conan learns a new phrase, something like "itzklobberintyme").  Once the dust settles, Ben collects the widget he's been sent after and our story is over.  I'd buy that!

Sunday, 2/21 toss-up: which animal name would make a better 60's Spider-Man villain - The Snapping Turtle, or The Hermit Crab?