It must be a monster pub int 2011
Written by Renee Tawa
Illustrator Bob Berry
Published 2011
Publisher Publications International
Series Play-a-Sound
ISBN 9781450808927

It Must Be a Monster! is a 2011 Sesame Street Play-a-Sound storybook. Abby Cadabby has a sleepover at Elmo's house, and everything seems scary in the dark. Elmo teaches her that when you turn on the light, you can see that there's nothing to be afraid of.

The book has six sound buttons, and a built-in light. Readers can turn on the light switch, and the light will turn on for 15 seconds.