The title of this article is conjectural. Although it is based on canonical information, the actual name is conjecture and may be supplanted at any time by additional information released from canonical sources. If this occurs, please move this page to the appropriate title.
Hagrid mentions that he tried to turn Dudley into a pig, but supposes that must not have worked because he was already too much like a pig. However, he might simply have been using the wrong spell. Alternatively, this is simply another instance of Hagrid's magic not working fully, due to his snapped wand.