noun
Explanation
The Joke
A couple is sitting on their roof at night when one of them spots the English Language personified as a figure approaching their house. The other is alarmed: "Oh no, it's--" and the English Language announces itself. What follows is a sequence of the English Language doing increasingly annoying things to the couple: barging into their home, being intrusive, and tormenting them. One person asks "Are you a noun?" and the English Language smugly responds with some kind of grammatical mischief. The couple grows increasingly distressed -- "Stop it!" "I can't take it! AAAAAAH!" -- as the English Language continues its assault. The final panel shows the defeated person sitting in the dark, muttering "I'd better make sure to conjugate my verbs correctly" -- having been terrorized into grammatical compliance.
The comic personifies the English language as a menacing home invader who torments people over their grammatical mistakes. It satirizes both the arbitrary complexity of English and the culture of aggressive grammar correction. The English Language itself is portrayed as an unreasonable bully -- which is fitting, given how inconsistent and illogical English grammar and usage rules often are.
The Humor
The humor comes from the absurdist premise of the English Language as a physical entity that can break into your house and terrorize you. It plays on the anxiety many people feel about making grammatical errors, escalating that anxiety to the level of a horror movie. The final panel -- the traumatized victim resolving to conjugate correctly -- is funny because it shows the intimidation working, which is essentially how prescriptive grammar policing functions in real life, just without the home invasion.
References
The comic satirizes prescriptive grammar culture and the long-running debates between linguistic prescriptivists (who insist on "correct" usage) and descriptivists (who study how language is actually used). The personification of language as a threatening force echoes a common SMBC theme of abstract concepts manifesting as characters.