X-Men #19 (Apr 66): Lo! Now Shall Appear the Mimic!Creative Team: Stan Lee, story; Jay Gavin, pencils; Dick Ayers, inking; Artie Simek, lettering; (all that, and forbush too!)
Starting Line Up: Cyclops, Iceman, Angel, Beast, Marvel Girl
Synopsis: Iceman and Beast are on a double date with Zelda and Vera Cantor. They run into Calvin Rankin, who mimics powers of people around him. His father was a scientist whose experiment accidentally transformed his son. His father was working on a machine to augment the powers, but it was buried in an underground base (and the father killed). Mimic then runs into Marvel Girl, whose powers he also mimics. He follows her back to the X-mansion. Once he gets everyone's powers, he kindaps Marvel Girl and takes her to the underground lab (and Cyclops is extremely worried). When they arrive to rescue her (Cyclops acts like he doesn't care), he uses their powers to uncover the machine. The machine turns out to actually remove his powers. Xavier wipes his mind.
Yeah, but is it good? It's ok. It was only a matter of time until the X-Men met their evil twin. It's too bad the Mimic isn't that exciting. He goes on to be the first new member to join the team, but only lasts three issues. That happens later, not here. The Mimic has never been important, so this issue isn't very much. Cyke getting all worried about Marvel Girl then ignoring her when she's rescued is pretty funny, though.
Significata: First appearance of the Mimic. Worst title ever!