Imaginary / by Lee Bacon ; illustrated by Katy Wu.

Enhanced descriptions from Syndetics:

Zach should've outgrown his imaginary friend by now. He knows this. He's 11, long past the days when kids are supposed to go on epic make-believe adventures with their invisible friends. But after the death of his father five years ago, all Zach wanted was an escape from the real world. So his imaginary friend, Shovel, hasn't faded away like the other kids' have. Their imaginary friendship grew stronger. But now Zach's in middle school, and things are getting awkward. His best friend ditched him for a cooler crowd. His classmates tease him in the hallways. He still misses his dad. Reality is the worst. Which is why Zach makes regular visits to a fantasy world with Shovel. But is Zach's overactive imagination helping him deal with loss or just pushing people away? Poignant, humorous, and breathtaking, Imaginary is an inventive story of friendship, loss, and growing up . . . as only an imaginary friend could tell it.