"Dreams End, Chapter 1: Rude Awakenings"
The X-Men are summoned by Professor X, he feels that they have become too lax in their training and orders a strenuous session in the danger room. While in there, Professor X calls on Marrow and challenges her to control her bone growth and pushes really hard over the protests of Ororo. The other X-Men confront Charles who seems very distant from the group. Later, Ororo and Kurt go to confront the Professor but he will only speak to Ororo, leaving Kurt outside to wait. Ororo emerges from the study but offers no explanation on what they spoke about or why the Professor is acting so strangely.
Xavier disbands the X-Men in this issue.
SPOILER: It was revealed in Uncanny X-Men (1981) #375 that the Wolverine in this issue was a Skrull imposter.