I've talked about the problem that DC faced with Superboy in the past. Essentially you've got a character whose adventures are happening roughly 10-12 years in the past; how do you avoid making him seem dull and behind the times? How can he be relevant to the youth of the 1960s and 1970s while constantly living with the trends of a decade earlier?
The problem was compounded by his earthly parents, Jonathan and Martha Kent. They were always portrayed as an elderly couple, childless, who happily adopted the baby Kal-El as the son they'd always wanted. But most children did not have elderly parents unless they (the kids) were tail-enders, late surprises in a mature family.
So in Superboy #145, DC decided to do something about it. The Kents would be changed to a couple more fitting with DC's target demographic's parents, in their mid-late 30s. And in a slap at their readers they didn't even hide their reasoning. They postulated a world which waited eagerly for new instalments of a fictional character named Superboy. But (as you probably guessed) this world was not our own, since Superboy had "real" adventures there. No, it was a world in space where an unscrupulous producer was filming Superboy's adventures and selling them as dramatic entertainment.
But the producer had the same problem DC had:
Well, of course the producer hits on the idea of making the Kents look younger, thereby bailing himself (and DC) out of the jam. He manages to send a bottle of youth elixir to the Kent's well, which results in them becoming younger. Although this is of course a boon in some ways, they worry that people will suspect a connection to Superboy and thus deduce his identity. So they arrange for a group of the Kents' oldster friends to come to a party where they can also enjoy the benefits of rejuvenation. Superboy fakes a comet passing by which is credited with the amazing transformation:
The results are a nice bit in an otherwise transparent attempt to make a major change to a significant character in the DC mythos. More important, it created just as many problems as it solved. Since the beginning of Superman, Clark Kent had never had a family as a young newsman in Metropolis. We never (almost literally never) saw his parents until the advent of the Superboy series; it was certainly understood that Superman had grown up as Clark Kent with an elderly couple, who had died.
A few years prior to this story, DC had finally created the story where the Kents passed away, in The Last Days of Ma and Pa Kent. While vacationing in the Caribbean, the couple had found a buried chest. Superboy humors their desire to go back 250 years in time to see the chest initially being buried.
Later, when they become ill, he mistakenly believes it's from eating a fruit they found in the past, but actually it was a virus contained in the treasure chest, so it wasn't Superboy's fault.
What was Superboy's fault was that they died as old folks, and now we were being encouraged to believe that they could not have been old. So when DC reprinted the story in Superboy #165, they actually redrew the artwork to make it look like the Kents were still fairly young:
But of course this actually makes the tragedy of their deaths even sadder.