"The most ungrateful of all voices surely is the voice of asses" (Koran xxxl. 18); and hence the "braying of hell" (Koran lxvii. 7). The vulgar still believe that the donkey brays when seeing the Devil. "The last animal which entered the Ark with Noah was the Ass to whose tail Iblis was clinging. At the threshold the ass seemed troubled and could enter no further when Noah said to him:--Fie upon thee! come in. But as the ass was still troubled and did not advance Noah cried:--Come in, though the Devil be with thee!; so the ass entered and with him Iblis. Thereupon Noah asked:--O enemy of Allah who brought thee into the Ark?; and Iblis answered:--Thou art the man, for thou saidest to the ass, come in though the Devil be with thee!" (Kitab al-Unwan fi Makaid al-Niswan quoted by Lane ii.45, per Burton's Alf Laylah wa Laylah III.117 n.2)I snagged this admirable reference as a happy byproduct of reading Declare by Tim Powers.