A particularly dark example of satire comes when Huck comes to at the Grangerfords's place. The Grangerfords are a fantastically wealthy family who live in an enormous house. They're the very epitome of social respectability in Huck's part of the world. And yet, in addition to owning a large number of slaves, they're also engaged in a bloody, long-standing feud with a neighboring family called the Shepherdsons.
What Twain is satirizing here is the huge gap between how so-called civilized people see themselves and how they actually are. Not too many people today would find feuding and slave-owning to be particularly civilized, and nor does Twain. The scene in which the Grangerfords and the Shepherdsons turn up for church one morning, fully-armed, is an especially brutal dissection of the hypocrisies of the world in which these families live, with its warped code of honor.
Mark Twain's The Adventures of Huckleberry Finn is a brilliant satirical piece, and there are many ways in which Twain lampoons his targets. One of the best examples of satire in the novel occurs toward the end, when Tom Sawyer hatches a ridiculously elaborate plan to free Jim.
While Huck wants to free Jim from his prison on the Phelps' property using the easiest and most efficient method, Tom concocts a needlessly elaborate scheme. Rather than simply freeing Jim by means of a poorly blocked window in his prison, Tom proposes that he and Huck dig Jim out (229), saying that this scheme is better because it's more complicated. Additionally, Tom refuses to use picks and shovels to dig out Jim, but rather insists on using much less effective case knives (237). Finally, after doing many more foolish things, Tom insists on actually writing letters to the Phelps advising them that an escape is imminent, as he believes that doing so will heighten the excitement of the escape (261-2).
Tom follows this absurd plan in order to emulate the romantic adventure novels he is infatuated with. For instance, when Huck asks him why he wants to use case knives, Tom insists "it's the regular way. And there ain't no other way, that ever I heard of, and I've read all the books that gives any information about these things" (237). Here, and later on in the passage, Tom alludes to reading and drawing inspiration from historical romances and adventure novels, and so he bases his plan on an absurd, irrational, and fictional portrayal of chivalric adventures. By presenting the themes in historical romances as the games of mere boys, Twain brilliantly satirizes them.