It's beginning to look more and more to me that any Superman or Superboy story published after 1967 (which I now consider to be the end of the Silver Age) but before 1970 (the launch of the Bronze Age) takes place in a separate Mad-like continuity. The other tale here at Superman Thru the Ages! that falls in the same category is "The Strange Death of Superboy!"
Superboy was actually experimenting with some darker stories at that time (or at least 3 or 4 of the total of 5 Superboys I bought between 1967-70), issues where Superboy or Clark needed to leave Smallville because of a threat of some type and initially setting up an expectation where there's abandonment.
The second Virus-X storyline was published in 1968 and thus also falls in this window. More evidence for my argument.
I did laugh at the plastic covering on his brain too...
As if there's any reason that should somehow block someone from being hypnotizable.