Weird
Explanation
This comic is a wordplay joke built on the etymology of the word "weird."
In the first panel, a man tells Sally "I like you, but you weird me out." Sally responds by asking whether he means "weird" in the archaic verb sense -- "to foretell doom" -- which is indeed the original Old English meaning of the word "wyrd" (fate, destiny). The three "Weird Sisters" in Macbeth, for instance, are called "weird" because they prophesy, not because they're strange.
The man is startled: "How did you know I was weirding you?" -- confirming that yes, Sally has in fact been foretelling his doom, not merely being strange.
Sally responds "See, it's this sort of thing" and then adds "I guess that explains why you want me out, though." The joke operates on multiple levels: Sally is "weird" in both the modern sense (she's an odd person who knows obscure etymology) and the archaic sense (she literally foretells doom). Her knowledge of the word's etymology is itself an example of the kind of behavior that makes her "weird" in the modern sense, while her actual ability to foretell doom makes her "weird" in the original sense.
The comic is a classic SMBC linguistic joke, finding humor in the gap between a word's contemporary meaning and its historical one, and then collapsing that gap by having a character who embodies both meanings simultaneously.