Chris Van Allsburg's Monsieur Bibot is a very sadistic French dentist who is given a pair of magic figs as a form of payment by an impoverished patient. The fruit has the power to make dreams come true, according to the old woman, but he scoffs at the idea until after eating the first one, he realizes that his dreams have indeed come true.
Bibot makes plans for the second fig, including ditching his abused terrier for a string of Great Danes when in a twist of irony Bibot's relationship with Marcel (his terrier) changes drastically.
What it looks like in the Middle:
This picture book with its sepia-toned illustrations and its extreme angles lends mood and tone to this story, which can be a lesson by itself, but I like to introduce irony with this book.
As we're going through the story, and as the students are immersed in the illustrations, they are asked to make some predictions, and at the end they get to "see" irony and are able to define it in a student-friendly way.
When we follow this up with a classic middle school short story like Guy de Maupassant's "The Necklace," they get the concept of irony faster by doing some ground work ahead of time.