Half-Blood Prince

When Sirius Black dies at the end of Harry Potter and the Order of the Phoenix, he leaves behind several survivors, notably the house-elf Kreacher and his pet Hippogriff, Buckbeak. While Kreacher was taking care of himself for several years while Sirius was incarcerated, and so is not much of a concern, Buckbeak has no such resources and must be cared for by someone... and who better than Rubeus Hagrid, who had been caring for him originally? Of course, Buckbeak was supposed to be executed, so he cannot return under that name; Hagrid renames him to keep the Ministry from trying again.

While he is referred to as Witherwings a few times in the book, the deception is very thin; people don't seem to be able to remember that he is no longer called Buckbeak. Thus, all the events that occur to Witherwings are cataloged under the character entry for Buckbeak.