"Rickdependence Spray," the latest episode from Adult Swim's Planets Only, Story Train). But most times, they're an opportunity for the show to directly reference pop culture (Johnny Carson, Albert Einstein, and the complicated legacy of Michael Jackson). The post-credits scene from "Rickdependence Spray" falls into the third category.
In the scene, an astronaut repairs a satellite while remarking to himself about how the solitude of spacewalks helps him forget his emotional baggage. Suddenly, a massive, slightly deformed infant arises as the iconic tune of Richard Strauss' Also sprach Zarathustra begins to play. The child grabs the astronaut as they solemnly accept their fate, and it shakes him around like a rattle.
There are several references at play here, the most obvious of which is Gravity (2013) by portraying an astronaut on a spacewalk harboring unprocessed trauma, not unlike Sandra Bullock's character in the Alfonso Cuarón film (and with a disposition similar to George Clooney's character in the same).
A deconstruction of science fiction tropes from its inception, Rick and Morty is no stranger to referencing other media. The rest of "Rickdependence Day," itself punning on the title of The Lord of the Rings: The Two Towers (2002).
So will the United States, or perhaps more importantly the Smith family, have to worry about a giant orbiting incest baby in the coming episodes? Probably not. Post-credits scenes, while they certainly have fun melding the series' zany sci-fi concepts with broader pop-culture touchstones, rarely impact future Rick and Morty plot lines. But on rare occasions, the show strings together running gags included in the codas, so there's a chance audiences haven't seen the last of incest baby.