Fantastic Four #217

In "Masquerade!", Reed Richards trusts H.E.R.B.I.E. to strengthen the Baxter Building's defenses—unaware that the robot's programming hides a far more dangerous secret. With the Fantastic Four trapped and the building under siege, the team must uncover the truth behind their own guardian's betrayal before it's too late. Written by Marv Wolfman and Bill Mantlo, with dynamic art by John Byrne and Joe Sinnott, and a cover by Joe Sinnott, this 1980 issue delivers suspense and surprise in equal measure.