whistle
Explanation
The Joke
The comic describes a prank: over the course of several months, you slowly adjust the whistle on your roommate's teapot so that its sound becomes ever closer to their name being screamed. The victim hears the teapot and thinks, "Did it just... sounds weird, right?" while their companion responds, "What sounds weird?" -- implying the gradual change is so subtle that it is hard to pinpoint, but the victim has a growing, uneasy sense that their teapot is calling their name.
The Humor
The joke works because it describes an incredibly elaborate, slow-burn prank that exploits the psychological phenomenon of gradual normalization. By making tiny, incremental adjustments over months, the prankster ensures the victim never experiences a sudden enough change to raise alarm -- they just have a vague, creeping sense that something is wrong. The idea of a teapot that slowly starts to scream your name is inherently absurd and slightly horrifying, like a domestic appliance becoming sentient and hostile. The humor is also in the sheer commitment required -- this is not a quick joke but a months-long campaign of psychological warfare using only a tea kettle. The other person's obliviousness ("What sounds weird?") makes the victim doubt their own sanity, which is the hallmark of a truly excellent prank.