It seems a safe assumption this in-house ad was intended to showcase DC's outer space heroes, which makes the inclusion of the entirely earthbound Ambush Bug (who didn't even appear in any ongoing series for which to shill) all the more curious. Further, Green Lantern and J'Onn J'Onzz were both in under-performing, soon-to-be-cancelled titles, while hopes for the just-launched Hawkman were similarly misplaced. However, all three and Superman were part of the Super-Powers toy line, which allows me to explore my personal connection to this ad.
You see, when I started collecting comics, DC was already suffering near collapse in the marketplace. You could only find a few bestsellers and some new launches at the convenience stores I frequented in Texas (like "Teen Titans," "Warlord," and, honestly, "Blue Devil.") While Kenner's semi-popular toy line was introducing kids like myself to DC characters, the ball was getting fumbled at the newsstand, preventing DC from capitalizing on the interest. The only time I ever saw Justice League of America comics, for instance, was in older friend's collections. Those George Pérez covers would really grab my eye, before I'd crack the cover, see the interiors didn't match, and set the book right back down. I don't believe I so much as held a copy of a Detroit-era League comic until the mid-90's. So you might imagine, having bought the trés cool Martian Manhunter action figure back in '85, I was at a bit of a loss as to who this dude actually was.
On the other hand, I was very fond of the Son of Ambush Bug mini-series, which somehow made it to 7-11 for most of its run. In one early issue was this ad, likely the first time I'd ever seen J'Onn J'Onzz in an actual comic book (as opposed to the rinky-dink number packaged with the toy I lost nearly immediately after opening the package.) The striking image added to the mystique in my mind surrounding this still obscure hero. Who is the Manhunter from Mars? What were his powers again? I wouldn't begin to unravel the mystery for about another year, when a shopgirl at Waldenbooks thought I was just too cute in my Houston Oilers jacket and gave me a double-sized comic book off the rack. I saved it for a trip to Colorado, though that was a trial, as the interiors of "Crisis on Infinite Earths #7" did in fact match the glorious Pérez cover...
I'd love to find out who drew that Martian Manhunter image, and for what project. I initially assumed it was by Mike Nasser, based on the quality, prior association, and clear Neal Adams influence. That artist, now going by Michael Netzer, corrected my error, and we both figured it was Jose Luis Garcia-Lopez, though that remains unconfirmed. Any help on the matter would be appreciated.