This Is Not My Hat by Jon Klassen

From the creator of the #1 New York Times best-selling and award-winning children's book I Want My Hat Back comes a second wry tale from Jon Klassen. This Is Not My Hat  is the second book in Klassen's "hat" trilogy and won the Caldecott Medal in 2013. Recommended for kids ages 5 and up.

When a tiny fish shoots into view wearing a round blue topper (which happens to fit him perfectly), trouble could be following close behind. So it’s a good thing that enormous fish won’t wake up. And even if he does, it’s not like he’ll ever know what happened. . . . Visual humor swims to the fore as the best-selling Jon Klassen follows his breakout debut with another deadpan funny tale.