Bracegirdle, P.J. (2008). Fiendish Deeds.* (The Joy of Spooking, bk.1) Grades 4-7.
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As Joy sets out to find the truth behind the story and ventures into the bog with her less than enthusiastic brother, Byron, she hopes to find evidence of mysterious animals or plants so that she can prevent the waterpark from being built. Will she find the bog fiend or some other horrible creature lurking in the swamp? You'll have to read this book to find out.
*Request through interlibrary loan.