Uncanny X-Men - Chris Claremont VI.

X-Men v1 #125-128.

Mutant X is one of those stories. You know what I mean – a classic.

When the time came to reinterpret the X-Men mythos twenty years later, one of the first story arcs in Ultimate X-Men was a retelling of Mutant X. In fact, it arguably got one of the most faithful reinterpretations in the new series. Aside from the fact that it's a damn good story, the general affection for it is probably due to two facts: the figure of Proteus (whom I'll discuss more at the end) and the concision of the arc. Despite the laborious, long-reaching setup, the story itself is contained neatly in just four issues. This distinguished it among Claremont's web of plots, and made it stand out more than, say, the Phoenix Saga, which was composed of a lot of separate elements and was told over a longer period of time.