Seems appropriate that on 8/8, I present Mego's 8" Superman-related figures!
I'm not sure why Mr. Mxyzptlk was the only Superman villain done in this scale... seems to me that Luthor would've made a better addition to the line. Like most of the Megos, Mxy was available on card or in the box. I believe the carded figures were first, but I could be misremembering.
The Secret Identity figures (which included Clark Kent) were an exclusive item available only from the catalog of either Sears or Ward's.
This box was what stores received the boxed figures in, making a built-in display. There can't be too many of these out there!
Here's Supergirl in the card and box versions. I can't help but think the figure would've been improved by not having the "panty hose" leggings on it. The Wonder Woman figure had the same affliction.
And last, but not least, here's Superman himself!
I've always wondered why Mego didn't do a Superboy figure, or other Superman villains... Brainiac seems to me would've been an obvious addition to the line.