talking-is-weird
Explanation
The Joke
A character begins by observing that "talking is weird" and proceeds to deconstruct speech from a physicalist perspective: she is "just wobbling some mucus membranes" (vocal cords) which wobble the air, which wobbles bones in the listener's ear. She then marvels that specific wobbles can break hearts, cause joy, or drive someone to insanity. She continues that for any person, there exists some sequence of vocal fold wobbling that could produce just about any mental state. She then declares this is like having a superpower that only works once in a million attempts -- and asks "Hey, are you asleep?" Her conversation partner responds "Uh huh," having fallen asleep. The final panels reveal that her monologue has induced a "sudden state of somnolence" (sleepiness), and they dub her "Slumber Lass."
The Humor
The humor works on several levels. First, there is the genuinely interesting philosophical observation about how strange it is that vibrating flesh can transmit complex emotions and ideas -- a classic SMBC move of finding wonder in mundane physical processes. Second, the comic undercuts this profound observation by demonstrating it in the most unflattering way possible: rather than breaking a heart or inspiring joy, her particular sequence of "wobbles" has put someone to sleep. The superpower metaphor pays off perfectly -- she does have the ability to induce any mental state through speech, but the mental state she actually produces is unconsciousness, because her philosophical tangent is boring. The superhero name "Slumber Lass" adds a final layer of comic deflation to what started as an earnest meditation on the nature of language.