Ceres
Explanation
The Joke
A man excitedly announces that they have discovered water on Ceres (the dwarf planet in the asteroid belt). A woman dismissively asks "Who cares?" He responds that one day they could grow crops there. She counters that there is no point in growing crops on Ceres because it would cost a fortune for every grain. The man then delivers his pitch: "I've got three words for you: Onerous. Naming. Rights." The final panel, labeled "Soon...", shows a box of cereal branded as "Authentic CEREAL -- Grown in the Cereal Region of The Solar System."
The joke hinges on a fake-etymology wordplay. The dwarf planet Ceres shares its name with the Roman goddess of agriculture, from whom we also get the word "cereal." The man's scheme is that if you grow grain on Ceres, you can market it as authentic "cereal" -- literally grown in the Ceres region -- much like how Champagne can only be called Champagne if it comes from the Champagne region of France.
The Humor
The humor works on multiple levels. First, there is the absurdity of spending untold billions to grow crops on a distant dwarf planet purely for a branding gimmick. Second, there is the clever real-world linguistic connection: "cereal" genuinely does derive from Ceres, the goddess of grain and agriculture. The comic takes this etymological fact and imagines someone exploiting it as a geographic designation of origin -- a ludicrous but internally logical business plan. The phrase "onerous naming rights" also works as a joke, since "onerous" means burdensome or costly, which is exactly what this scheme would be.
References
Ceres is the largest object in the asteroid belt and was classified as a dwarf planet in 2006. NASA's Dawn spacecraft confirmed the presence of water ice on Ceres in 2015-2018. The word "cereal" does indeed derive from the Latin "Cerealis," referring to the Roman goddess Ceres. The concept of protected geographical designations (like Champagne, Parmesan, or Scotch whisky) is a real legal framework in international trade.