The Terror of Invisible Lucy!.Lucy bathes with a magical potion she created seven years ago, only to find that its effects have changed over the years to turn her entire body invisible. She turns to her friends for help, but their attempts to make her visible again by painting on her and masking her fail. Eventually the potion's effects become so severe that they cause Lucy to disappear together with everyone's memories of her as if she had never existed. Fortunately, Natsu is able to remember his friendship with Lucy, allowing everyone to recall her back into existence. As Happy hugs Lucy in joy, however, she accidentally spills the potion bottle over everyone else, turning all of them invisible.