§ Of Beren and Lúthien The Silmarillion

Then Beren perceived that Lúthien could not be divided from the doom that lay upon them both, and he sought no longer to dissuade her. By the counsel of Huan and the arts of Lúthien he was arrayed now in the hame of Draugluin, and she in the winged fell of Thuringwethil. Beren became in all things like a werewolf to look upon, save that in his eyes there shone a spirit grim indeed but clean; and horror was in his glance as he saw upon his flank a bat-like creature clinging with creased wings. Then howling under the moon he leaped down the hill, and the bat wheeled and flittered above him.