Insertion of over-specific detail to humorous effect

In Gilmore Girls, describing a debutante ball: "It's like animals being up for bid at the county fair, except sheep don't wear hoop skirts."

This kind of over-the-top, facetious detail is used throughout the show and fuels the witty dialogue. Is there a word for humor created by such an unexpected, specific detail?

This question suggests "facetious synecdoche," but I don't think the example above is synecdoche (except for "sheep" being representative of "animals", but it's really the "hoop skirts" that drives the humor). I'm also not looking for: "detail," "imagery," "satire," "hyperbole."

Solution 1:

In comedy, this is called tagging a joke. The tag is a following reference to the punchline that adds comedic effect. Here the (supposedly) amusing punch is the comparison of debutantes at a ball to farm animals to be judged at a fair. The tag is the mention by denial of hoop skirts on sheep, which attire is suitable only for debutantes, i.e., neither for sheep nor for reasonable women.