Junie B. Jones Has a Monster Under Her Bed is the eighth book in the Junie B. Jones series.
During Picture Day when Junie B. is told by Paulie Allen Puffer that a monster lurks under her bed, rekindling her fear of monsters, she takes desperate actions to make it go away, which also causes her to get less sleep.
At class picture day, Paulie Allen Puffer tells Junie B. about how his brother told him that monsters live under everyone's beds. Junie B. gets scared and accidentally ruins her class photo as a result. Her fears only get worse when Grace tells her that its possible a monster is under the bed, because they can turn themselves invisible.