This is Not My Hat by Jon Klassen
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. Ages 4 - 8 years.
2013 Caldecott Medal winner.
Hardcover, 8.25" x 11.25"; 40 pages