The Wishing Stone

Be very, very careful what you wish for in this ninth book in the Spooksville series New York Times bestselling author Christopher Pike.
While hiking in the woods near Spooksville, Adam and his friends find a cube-shaped stone. It is clear, like a crystal, and seems to shine with colored light. To their surprise, they discover that if they hold it and make a wish for something, the wish will come true! They call it the Wishing Stone. And they love it. Until they discover that there is a price to be paid for each wish…and that the price can be deadly.