Appearing in "The Mutants and the Monster"
- The X-Men
- US Army
- Unnamed army soldiers
- Unnamed Las Vegas citizens
- United States
- Cyclops' Visor, version 1
- Dr. Pym's Mind-Probe apparatus
- Dr. Banner's Gamma-Ray device
- X-Men's Sentinel Ship
Synopsis for "The Mutants and the Monster"
Having used his mental powers to save the world from an invasion from the deadly Z'nox race, Professor Xavier is on the brink of death and in a coma state. The X-Men mourn over the Professor's condition when Havok goes to comfort Lorna. This prompts Iceman to attack him out of jealousy for making a "move" on his girl. Before a fight can break out, Cyclops breaks it up, and both men are chastised by Lorna who tells them that the Professor's condition is more important than their rivalry for her affections. The two quarreling men then bury the hatchet for the sake of the others.
By this time, Beast has rigged up a machine that will probe the Professor's mind and allow a projection of the Professor's head tell them the thoughts that are on his mind. Doing so, the Professor can only say that he needs to find the Hulk before it's too late. Not wishing to harm the Professor with the device, they turn it off and have Marvel Girl probe the Professor's mind further to try and learn more, but all they can gleam is that the Hulk has some key to the Professor’s recovery. Cyclops realizes that it's probably the Hulk's alter ego, Bruce Banner, whom the Professor is referring too and the group decides to seek out the Hulk to try and get Banner's aid in saving the Professor's life.
While Cyclops, Marvel Girl, Angel and Beast go out to find the Hulk, Havok and Lorna decide to stay behind and watch the Professor, with the jealous Iceman also deciding to stay behind to keep an eye on Havok. The X-Men track down the Hulk who is currently on a rampage in Las Vegas. The X-Men engage the Hulk but Cyclops, Angel, and Beast's attacks on the jade giant prove ineffective. It's not until Jean unleashes a mental bolt on the Hulk that they have any effect on his rampage. The strain of the mental attack causes the Hulk to revert into Bruce Banner. Before the X-Men can get any answers out of Banner, Glenn Talbot arrives with the military and demands that the X-Men step aside and allow him to take Banner into custody. When Cyclops tries to explain that they need Banner's help to save Professor Xavier's life, the awakening Banner recalls that he has a Gamma-Ray powered device that can cure mental exhaustion and that the device is in one of his hidden desert labs.
However, unwilling to help out the X-Men, Talbot orders his troops forward and their advancement excites Bruce enough to cause him to transform into the Hulk once more. The Hulk then makes short work of a tank before jumping off to escape so that he can be alone. The X-Men and the military both split up to attack the Hulk. The X-Men's ship proves to be faster and they track the Hulk out into the Nevada desert. There they battle the monster, and in the wake of the battle, the Hulk inadvertently uncovers the hidden lab that his alter-ego was talking about.
Sending Angel in to recover the device, the other X-Men hold off the Hulk. The Hulk manages to overpower them, almost sending Cyclops and Marvel Girl for a nasty fall when he smashes the group open. They are saved by Beast and the group manages to make their escape. Returning to the X-Mansion, they are reunited with Havok, Lorna and Iceman for the moment of truth. Activating the device, the X-Men are pleasantly surprised to find it worked when the Professor awakens, completely cured of his affliction. With the crisis over, the Professor thanks his students for saving his life.
- (May) The target is the Hulk—the scene is Las Vegas—and the stakes are the life of Professor X! The greatest mutant masterwork yet!
- This is the last issue before X-Men becomes a reprint title. It will remain in reprints until 1975 and the publication of Giant-Size X-Men.
- Amazing Adventures (Vol. 2) #12 reveals that due to the public backlash of their fight in Las Vegas, the X-Men went into hiding for several years, explaining why they stopped appearing as frequently after the series was cancelled.
- In 1999-2000, John Byrne would write and pencil X-Men The Hidden Years. In the same vein as Untold Tales of Spider-Man, it detailed early adventures of the X-Men. However, unlike Untold Tales, which told early Spider-Man adventures that happened in between stories written during the Stan Lee/Steve Ditko run of Amazing Spider-Man, The Hidden Years told the adventures of the X-Men between X-Men Vol 1 66 and Giant-Size X-Men Vol 1 1, the series was canceled after 22 issues. A preview of the series was published in the back-up story to X-Men (Vol. 2) #94, which chronologically occurs following this issue.
- references: X-Men #65 and Avengers #68
- The Beast makes the comment, "I scrambled up the cliffside in the best traditions of Justice Douglas," while sneaking up on the Hulk. Presumably, he is referring to noted environmentalist Justice William O. Douglas.