The cover artwork shows an unspecified beast in ripped pants with the full moon in the background.
On Halloween night, siblings Robbie and Alesha go trick-or-treating around town. They reluctantly visit the home of one of their nastiest teachers, Mrs. Eakins, who they'd recently upset by kicking a soccer ball through her window. When they arrive at her home, however, they are surprised to find that the usually mean Mrs. Eakins is being so friendly. Mrs. Eakins generously gives them both full-size candy bars which the two gobble up on the way back.
The next morning, Robbie discovers that he is completely coated in thick hair, just like a werewolf. Robbie can't talk and finds that he is constantly hungry and unable to control his appetites, eating anything he can - including live animals. Robbie finds Alesha and the two flee into the woods nearby, away from the police who are pursuing them.
After regaining their speech, Robbie and Alesha plan what to do. They worry that they have succumbed to a mythical illness called "Full-Moon Fever," which turns anyone who looks at the full moon into ravenous, snarling beasts. Robbie and Alesha go to find their Grandpa John, who told them about the disease the night before, only to discover that it is merely an old legend and that it isn't real.
The two travel to Canada to find a cure -- only to be captured by a circus ringleader who turns them into circus freaks. They escape the circus and try to change back under a full moon, only to find it has no effect. They return home with Grandpa John and find Robbie's Halloween candy, including a "Beast" bar, leading Robbie and Alesha to deduce that the candy bars Mrs. Eakins gave them were actually cursed and she is a witch.
Robbie and Alesha go to Mrs. Eakins' home and attack her after ransacking the house. They eat many "Cure Bars", which were lying around the house and hope that they will cure them. However, Robbie takes another look at the label and discovers that they actually say "Curse Bar", meaning that they have just likely permanently cursed themselves.
- This book's title is a reference to the Tom Petty album Full Moon Fever.
- The book's plot resembles an earlier short story, Pumpkin Juice, from Still More Tales to Give You Goosebumps.
|Goosebumps Series 2000 series|
|#01 Cry of the Cat||#10 Headless Halloween||#18 Horrors of the Black Ring|
|#02 Bride of the Living Dummy||#11 Attack of the Graveyard Ghouls||#19 Return to Ghost Camp|
|#03 Creature Teacher||#12 Brain Juice||#20 Be Afraid – Be Very Afraid!|
|#04 Invasion of the Body Squeezers: Part 1||#13 Return to HorrorLand||#21 The Haunted Car|
|#05 Invasion of the Body Squeezers: Part 2||#14 Jekyll and Heidi||#22 Full Moon Fever|
|#06 I Am Your Evil Twin||#15 Scream School||#23 Slappy's Nightmare|
|#07 Revenge R Us||#16 The Mummy Walks||#24 Earth Geeks Must Go!|
|#08 Fright Camp||#17 The Werewolf in the Living Room||#25 Ghost in the Mirror|
|#09 Are You Terrified Yet?|