Uncanny X-Men Vol.1 #11
Xavier detects an extremely powerful entity that has arrived on earth and sends the X-Men to investigate; The Stranger tries to acclimate himself to earth customs but runs across Magneto and the Brotherhood; The X-Men arrive on the scene and battle the Brotherhood but the Stranger leaves with Magneto and Toad in the conflict; Without a leader, Quicksilver and the Scarlet Witch decide to return home to Central Europe; The X-Men encounter the Stranger once again and Xavier realizes he is an alien; The Stranger explains that he has been collecting mutants from across the universe and takes Magneto and Toad away with him into space.
Printed: May 1965
Writers: Stan Lee
Art: Jack Kirby and Chic Stone
Cover: Jack Kirby and Chic Stone