Here are two suggestions from Targuman, not very similar except that in both getting the joke depends on catching a cultural reference. Not entirely a geezerish enterprise, either — yes, both have roots in the sixties or before, but at least one is still in use in contemporary “intellectual properties”.
“Andy”?? How about Johnny and Henry? (Okay, yes, we know why. But strictly speaking it’s a mistake.)
So, some confusion between Nirvana and reincarnation / transmigration of souls?
Comics I Don't Understand 
First one: Moon River ?
The second one: Batman’s sidekick has turned into a real robin. No need to go back in time to get that one.
Oh, and the artist clearly has no idea what a robin actually looks like. Only the red patch indicated what kind of bird it is. If I’d seen it in greyscale I would have taken it for a pigeon.
Regarding the first one, I’d say that most people don’t know that Henry Mancini and Johnny Mercer wrote Moon River, but they know that Andy Williams sang it. I didn’t until I looked it up. Also, it doesn’t look wider than a mile to me. :)
I knew that Henry Mancini wrote “Moon River” but not that Andy Williams sang it so I was very confused.
Batman’s sidekick has turned into a real Robin, thus reaching Nirvana?
@ Maggie (5) – That’s the joke, but following onto Pete’s comment @2, I think Robin should have watched the movie “Spies in Disguise” before attempting the transformation.
@ Rob W.(3)
Remember that the Moon has no atmosphere. The appearance of distance can be deceiving because distant objects are seen just as clearly as nearby ones, i.e. no atmospheric haze at the other side of the river.
@ Nebulous (7) – The elimination of the haze effects might affect the appearance of the length of the river, but surely not the width. I agree that the perspective and the depth of the canyon indicate that it is (much) wider than the astronaut, but it still does not appear to be anywhere near a mile wide.
P.S. As long as we are discussing factors related to the suspension of comic disbelief, the lack of atmosphere would cause any body of open water on the moon to evaporate fairly quickly, especially since the daytime (sunlit) surface temparature is well over the boiling point of water. Space scientists are still clinging to the possibility of finding water on the moon, but the best they can hope for are mineral hydrates, or minor amounts of fossil ice hidden in craters near the poles (which is the target of the lander that India just recently launched).
@Rob W: ” it doesn’t look wider than a mile to me”
No, but with the moon’s lower gravity, maybe he would be able to jump it, which would certainly be “crossing in style”.
Rob: You mean it’s not “wider than a smile”?
The Chuckle Brothers reference is not as outdated as you might think, since that comic is from 2014.
One would assume any rivers on the moon would have been visible when NASA was mapping out landing locations. :-p
@ Carl Fink (11) – One thing that would be a gigantic improvement in the GoComics website would be if they added a “dagger” mark (“†”) after every single rerun feature that is no longer being produced. The percentage may be frightfully high, but still, it would make it easier to concentrate on living artists.
Of course there are rivers on the Moon. They flow into the seas and oceans. Duh.
I can imagine the Yelp review for the first restaurant on the moon.
“Nice seaside location but no atmosphere”.
@Grawlix, I went to the wedding of two antennas. Frankly, the ceremony itself wasn’t that special — but the reception was great!