Nudge
Explanation
The Joke
The comic features two alien creatures (who appear to be reptilian or dinosaur-like) discussing recent events. One reports good news: an asteroid missed their planet by over 200,000 miles. However, the emergency asteroid deflection program is going to lose its funding, which will be redirected to "a bunch of dental stuff." The second alien proposes a thought experiment: "What if we keep this asteroid deflection spacecraft around for a while and nudge some small, cold-adapted mammals?" — suggesting they could redirect an asteroid toward another planet's small mammals. The final panel shows a wooly mammoth-like creature, and one alien says "I guess we shouldn't" while the other says "Unless we should."
The comic is a playful alternate explanation for the asteroid impact that caused the extinction of the dinosaurs (and many other species) approximately 66 million years ago. Instead of being a random cosmic event, the comic suggests it was a deliberate act by aliens from another planet who redirected an asteroid toward Earth's large mammals (or dinosaurs redirecting one toward Earth's mammals). The joke plays with the idea that catastrophic extinction events might just be the result of bored aliens with leftover space hardware.
The Humor
The humor works through the absurd casualness with which the aliens discuss redirecting an asteroid to kill creatures on another planet. The setup about losing funding for the deflection program is a recognizable satire of government budget priorities — cutting a critical space defense program in favor of something mundane like dental work. The punchline escalates when they realize the same technology used for planetary defense could be weaponized against unsuspecting creatures elsewhere, and their half-hearted moral deliberation ("I guess we shouldn't... unless we should") perfectly captures the way terrible decisions get made when bored people have access to powerful tools. The visual gag of the wooly mammoth looking oblivious adds to the dark comedy.