IRON MAN versus CAPTAIN AMERICA
The Terminus Factor Part One of Five: You are what you eat (Marvel comics)
Where: Captain America Annual #9 When: 1990
Why: Roy Thomas & Dann Thomas How: Jim Valentino
The story so far...
When Sherlock Holmes isn't cracking cases, he shoots heroin. Which is, frankly, why Holmes is nothing but a skinny elbowed English nancy.
Scoffing the most lethal of dangers, Captain America decides to volunteer for an experimental mission to pilot a Stark funded vessel to the center of a newly formed volcano. Why? Well, formerlyto protect Persephone-1 from sabotage, but really, just because he's that good. Human, too.
Things get ugly when a cybernetic egg planted by Terminus begins to crack, and a glowing lot of weird stuff starts to wreak havoc on the mission. Only by the intervention of Iron Man (who just happens to turn up as Mr. Stark disappears...) do Cap and the pilot escape with their lives -- but so too does the Terminus goo! Hitting a local waterstream has a strange effect on the fish that swim through it, and subsequently the bear who eats the fish, and so, Terminus enters the circle of life... and the water supply.
Full Article: http://secretearths.blogspot.com/2006/08/iron-man-versus-captain-america.html