I Need my Monster by Amanda Noll, illustrated by Howard McWilliam

From chapters.ca:
A unique monster- under- the- bed story with the perfect balance of giggles and shivers, this picture book relies on the power of humor over fear, appeals to a child's love for creatures both alarming and absurd, and glorifies the scope of a child's imagination. One night, when Ethan checks under his bed for his monster, Gabe, he finds a note from him instead: "Gone fishing. Back in a week." Ethan knows that without Gabe's familiar nightly scares he doesn't stand a chance of getting to sleep, so Ethan interviews potential substitutes to see if they've got the right equipment for the job - pointy teeth, sharp claws, and a long tail - but none of them proves scary enough for Ethan.