Some examples of this include:
—Gross, icky, silly,or sassy words
—Big words, lo-o-o-o-o-ng words
—Internal rhyme
—Puns
Many books make use of these devices, but here are two of my favorites.

“An egg is clever.”
“An egg is artistic.”
“An egg is textured.”
“An egg is giving.”
Most children (and adults) have never thought of an egg in these ways before. It is only after reading the smaller, supporting text scattered across the pages that the full meaning of the main text becomes clear. This sort of mysteriousness makes the book more engaging.

Each night thousands of herrings release streams of bubbles from their back sides. That’s right: fish farts. Well, sort of. To be true flatulence—that’s the scientific word for “fart”—the gas should come from digesting food. Burt herring FaRTs (Fast Repetitive Ticks) come from air herring have gulped at the surface, not from the food the fish have eaten.
What reader wouldn’t be intrigued by that?
These kinds of examples make us remember a book, so I’m willing to bet you can think of some books with text that surprised and delighted you the first time you read them. Feel free to share examples in the comments.