destroy
Explanation
The Joke
An elderly woman sits on a park bench, feeding pigeons. She says, "Go, my pretties. Kill! Destroy!" as the pigeons waddle around her feet. The caption below reads: "Finding out that pigeons are invasive pests really added zest to Agnes' afternoons."
The comic takes the wholesome, familiar image of a sweet old lady feeding birds in the park and recontextualizes it. Once Agnes learned that pigeons are actually considered invasive pests in many environments, her innocent hobby of feeding them transformed in her mind into an act of ecological warfare. She is no longer just a kindly grandmother enjoying nature -- she is now a supervillain deploying her army of invasive species to wreak havoc, and she is loving every minute of it.
The Humor
The humor comes from the contrast between the gentle visual of a grandmotherly figure on a park bench and the melodramatic villain dialogue ("Go, my pretties! Kill! Destroy!"), which evokes the Wicked Witch of the West. The joke also plays on how learning a single new fact can completely reframe an ordinary activity. Agnes's afternoons were presumably pleasant before, but now that she has the narrative that she is unleashing destruction, they have become exciting. It is a lighthearted commentary on how people can find motivation and meaning in the strangest rationalizations.
References
"Go, my pretties" is an allusion to the Wicked Witch of the West's famous line from The Wizard of Oz ("Fly, my pretties!"), further reinforcing the comic villain imagery. The factual basis of the joke is real: rock pigeons (Columba livia) are indeed considered invasive species in North America and many other regions, having been introduced from Europe.