The X-Men are working out in the Danger Room when the evil aspect of Xavier's mind attacks them with versions of the old X-Men. A fill-in issue that Classic X-Men skipped for reprinting. The story that began in Uncanny X-Men #105 continues in Uncanny X-Men #107.
Printed: Aug 1977
Writers: Chris Claremont and Bill Mantlo
Art: Dave Cockrum, Bob Brown, and Tom Sutton
Cover: Dave Cockrum
- 1st appearance of the Entity, the dark side of Professor X
- There are similarities between the Entity and Onslaught although the Entity is Xavier's dark side while Onslaught is the manifestation of Xavier and Magento's dark sides
