In a joke that implies DC and Marvel Comics share a multiverse, Booster Gold cracked an Avengers joke in yesterday's Action Comics #998, then followed it up with a crack that he was kidding -- after all, that's a whole different timeline.

Joking that he could call Skeets "Jarvis" -- the name of the Avengers' butler and, in the movies, the artificial intelligence among Iron Man's suit -- Booster dropped the "timeline" joke, which throws fuel on a fire already going with some fans because in a Marvel comic last week, a slightly-recolored version of DC's Shazam, formerly known as Captain Marvel, appeared in a page depicting alternate universe Captain Marvels.

People, then, who already took it as an implication that Marvel's multiverse shares worlds with DC's, looked at the Action Comics joke as confirmation.

DC, since 2005's Infinite Crisis, has had a limited multiverse: dozens of worlds (52, in fact) have been accounted for, with a fifty-third recently added (plus the Dark Multiverse).

The 2015 crossover event Convergence ostensibly re-established an infinite multiverse, but when the series proved less popular than hoped with fans, it seems that the fallout from the event was largely discarded.

Marvel's own multiverse was destroyed and rebuilt around that same time in the Secret Wars event.

Marvel and DC both have popular pastiches of one another's heroes appearing as villains: Marvel's "evil Justice League" is the Squadron Supreme, while DC's "evil Avengers" are Lord Havok and the Extremists. While the Extremists hail from another world in the DC multiverse, which was destroyed before they came, the current version of the Squadron Supreme exist in the standard Marvel Universe.

Of course, the "JARVIS" joke was a reference to the movies, not to the comics, and so it could be argued that Booster was referencing the Marvel Cinematic Universe.

If you are in the business of overthinking things, that is.

In the same way, one could argue that Booster Gold, a Time Master whose job it is to wipe out anomalous timelines created by people who mess with the timeline, would not use the word "timeline" imprecisely and that the Marvel Universe is not another Earth in DC's multiverse but rather a possible alternate version of the main DCU.

While technically Marvel and DC employees generally say that the two do not share a metaphysical space, almost every crossover between the two takes for granted that they are simply different Earths separated by space/time, suggesting that actually, they probably are.