A magic crystal?

By Louis Sachar

Subjects: Wishes, Friendship -- Fiction., Juvenile fiction, Wishes -- Fiction., Magic -- Fiction., Fiction, Marvin Redpost (Fictitious character), Wishes in fiction, Children's fiction, Friendship in fiction, Magic, fiction, Friendship, Magic, Magic in fiction, Humorous stories, Friendship, fiction

Description: When Marvin Redpost's new friend Casey shares with him her magic crystal that can make wishes come true, things get out of control.