I found out what had been battering Hagrid so badly, and oh, how I wished I hadn't! That utter madman had brought back a souvenir of his visit to the giants, in the form of his full-giant half-brother, Grawp! Sixteen feet tall if he's an inch, stupider than Malfoy's goons (at least that's the impression he gives) and stronger even than Hagrid! No wonder Hagrid had been so battered-looking!