Jacknapped: The Pumpkin Elf Mystery by Abby Klein

I have a problem, a really, really big problem. My class is having a pumpkin decorating contest, but my pumpkin has disappeared! Let me tell you about it.

It's almost Halloween, the time of year when teachers sometimes play a bit of trick or treat with their young students, and Freddy Thresher's teacher, Mrs. Wushy, is no exception. To gen up some excitement, Mrs. Wushy announces to her class that the "Pumpkin Elf" has visited her class during the night, leaving a pile of orange crayons and orange blocks scattered all over the floor and a mysterious pumpkin-shaped note on her desk. With a serious face, Mrs. Wushy reads the note to her amazed class:

I am the Pumpkin Elf and I'm here to say
That tomorrow might be your lucky day.
Listen to your teachers and you mom and dad, too.
And I might just leave something
Special for you!

Freddy and his classmates (Max the bully, Chloe the princess wannabe, Robbie the brainiac, and the others) are already excited when they arrive at school the next morning, only to find orange confetti, blocks, and crayons again scattered on the floor and a strategically-placed orange note stuck into their classroom calendar.

Step outside and do as I say.
Go to the place where you all like to play.

At the playground the class finds another orange note, which leads them first to the cafeteria, where a note in the lunch lady's pocket sends them to the library, where they spot another orange missive which sends them all to, of all places, the boys' restroom, always just a moment behind the elusive pumpkin-headed elf. Back in their classroom, however, the class finds that the elf has indeed left them a treat, a perfect-sized pumpkin for each student, which Mrs. Wushy explains they may decorate and enter into the holiday contest for the most original Jack-o'lantern in the group.

Freddy's big sister, who remembers the Pumpkin Elf well from her days in Mrs. Wushy's class, helps Freddy make a killer-diller carved pumpkin, a shark with huge, sharp teeth, scary eyes, and a black cardboard dorsal fin and tail. Freddy is sure he's going to win first prize, but when he puts the pumpkin on his front porch to keep it fresh, it disappears. The whole family rushes outside to do some detective work, and sure enough, it's not long before a suspicious suspect with pumpkin breath is "collared" for the theft. But how can Freddy go to school without a Jack-o'lantern on the day of the contest?

Pumpkin Elf Mystery (Ready, Freddy!) is a timely and Halloween-friendly sequel in the popular Ready Freddy series for beginning chapter book readers.