Ayesha revealing the creation of Adam Warlock
The most baffling post-credit scene could also have the biggest payoff. Guardians of the Galaxy Vol. 2 returns once more to the planet of The Sovereign to check in with Ayesha (Elizabeth Debicki) and her royally pissed off, golden race. Fuming over her back-to-back defeats, the empress mutters to herself about her next move, "the next step in our evolution -- more powerful, more beautiful, more capable of destroying the Guardians of the Galaxy." All we see is a cocoon of sorts, but fans of the comics know what's inside: Adam Warlock.
A key member of the Guardians of the Galaxy's comic counterparts, Adam Warlock's movie appearance always felt like a matter of when, not if. His origins are long and convoluted, first created in a lab on Earth, beaten to death by Thor, and later reborn by a mad, genetically altered scientist. The Guardians movies appear to streamline that a bit -- unlike comic Ayesha, Debicki's glowing queen is the leader of her technological society, and now she's overseeing the creation of Warlock, who in the source material is often associated as her equal and foster brother.
Whatever the case, the character is part of the Marvel Cinematic Universe, and his key trait could play a major part in future movies. Historically, Adam Warlock has possessed the "Soul Gem," one of the infinity stones that The Avengers' looming threat, Thanos, is out to collect. (If you recall, Star-Lord possessed one in the first Guardians: the Orb, aka the Power Stone.)
Simply put, if 2018's Avengers: Infinity War kicks off with Thanos collecting the stones, he'll have to encounter Warlock in one way or another. That could be a post-credits scene unto itself; according to Gunn, the character's expected to pop up in the inevitable Vol. 3, but not Infinity War. But the latter was originally conceived as a two-parter, meaning Thanos could pick up the Soul Gem between Infinity War and the yet-to-be-named final showdown movie, which conceivably loops in every character we've ever seen in these movies.
Whew. The Adam Warlock tease is a can of worms with endless possibilities. But expect at least one to take shape between now and the Guardians of the Galaxy's next appearance.