(Spoilers ahead for "Kong: Skull Island." So if you don't wanna know anything about the movie or what's in the big post-credits scene, walk away now and come back later.)
There are two big takeaways to be had from the "Kong: Skull Island" post-credits scene. First, that we haven't seen the last of Kong. And second, that there are more monsters out there.
The scene gives a good look at the future of the Kong franchise. It shows protagonists James Conrad (Tom Hiddleston) and Mason Weaver (Brie Larson) being told by the Project Monarch organization that more monsters are out there in the world. They show cave paintings of the other creatures.
One of them we know pretty well because there's been a million movies about it: Godzilla.
Godzilla is already part of Legendary Pictures "MonsterVerse," and Project Monarch appears in the 2014 reboot "Godzilla" -- they're the folks who have been studying these giant monsters for years, fearing their return. And we know that King Kong and Godzilla will meet in the future: Legendary has announced "Godzilla: King of the Monsters" for 2019 to sequel the 2014 movie, and "Godzilla vs. King Kong" in 2020.
Folks who aren't that familiar with the, ah, lore of Godzilla might not recognize the other monsters we get a glimpse at, but monster movie fans will likely identify the other creatures pretty quickly: Mothra, Rodan and King Ghidorah.
Those other monsters shown in the post-credits scene have faced off against both Godzilla and King Kong in past films. Mothra, introduced in the 1961 film "Mothra," is a giant moth that has fought Godzilla in movies a couple of times before. While Mothra doesn't usually have any problems with humanity, being a giant hungry bug still makes it pretty dangerous.
Rodan is basically a huge dinosaur, first appearing in "Rodan" in 1956. He's based on the pteranodon, and spends a lot of time flying and using his massive wings to ruin stuff. He's also battled Godzilla before, but the two monsters are generally allies -- except for when insidious extraterrestrial beings control Rodan's mind and turn him evil.
The guy Godzilla and Rodan usually beat down together is King Ghidorah, a three-headed dragon. First showing up in "Ghidorah, The Three-Headed Monster" in 1964, he sports two tails as well, which doesn't usually get mentioned. He can shoot "gravity beams" from his mouth, whatever those are, and create tornadoes with his tails.
So it seems Monarch has found at least a few other creatures to deal with. We know Godzilla and Kong are going to fight, but it's less clear whether Rodan, Mothra and King Ghidorah will get films of their own before they're thrown into the mix with their more famous counterparts. It seems a safe bet that at least one of the three will face off with Godzilla in "King of the Monsters," though with a title that grandiose they may all show up. But we have a couple years to wait before we find out for sure.