This story is a direct continuation of Riolu's At It Again! parts 1 and 2. There is a small story before this by another writter though. The always clever  Zee-Zee wrote a story about what happend to him after Riolu transformed him into a Pachirisu. You can check it out with this link.
http://lionstigerandligers.niceboar.....risu-t1973.htm

Ri's being returned to the Gittara household to face his punishment for his latest escapades. But what can they do to him in the gentle household where the worst they do is baby you as a punishment? Riolu might just have pushed Zoe into using something the family is normally against...