X-Men #29 seems to be the worst example yet of the Idiot Ball. Iceman, who it hilariously turns out is bad at ice-skating in his human form, is attacked by the Super-Adaptoid (an android which exhibits powers of four of the Avengers, introduced in Tales of Suspense the previous year), escapes, and reports to the X-Men, who refuse to believe him.
Mimic continues to act up, and starts fighting the other X-Men. The Professor is willing to take this up to a point, but when Mimic crosses the line, he sacks him from the X-Men, seemingly forgetting that Mimic had blackmailed his way on to the team in the first place. After Mimic leaves in disgrace, the Super-Adaptoid attacks, and Mimic comes back and saves the day, with his power causing a feedback loop with the Adaptoid's. They are both left depowered (although Mimic's first depowering didn't last long), and so Mimic leaves the X-Men again.
Meanwhile, Scott gets a very minor breakthrough as he realises he can control the intensity of his optic blasts slightly. He is able to stop the blasts with his eyelids, but then loses control. Jean is still at college, but is back with the team for this fight.