With the Avengers: Doomsday trailer showing the Avengers and X-Men fighting before presumably teaming up against a common threat, Polygon looks back at how rarely these two teams have actually clashed in Marvel's comic history. Despite decades of crossovers between individual heroes, full team-on-team battles between the Avengers and X-Men have been surprisingly uncommon, partly because the X-Men have historically operated in something of a separate bubble within the wider Marvel Universe.

The article highlights two early examples: their first-ever meeting in X-Men vol. 1 #9 (1964) by Stan Lee and Jack Kirby, a lighthearted Silver Age tale in which the outgunned original X-Men lineup barely puts up a fight against the classic Avengers; and Marvel Super Heroes Secret Wars #3 (1984), part of the pioneering Shooter/Zeck crossover in which heroes and villains are forced to fight each other on the alien "Battleworld", reportedly reflecting editor-in-chief Jim Shooter's own tensions with the X-Men titles at the time.