Ocnus

In Greek and Roman mythology, Ocnus or Bianor was a son of Manto and Tiberinus, king of Alba Longa. He founded modern Mantua in honor of his mother. Alternatively, he was the son or brother of Auletes and founded Felsina (modern Bologna), Perusia or Cesena.

Ocnus is thus a character or allegorical deity which personifies hesitation, frustration, delay and the wasting of time, thus symbolising the vicissitudes of human life consumed in unsuccessful efforts. He was condemned to spend eternity in the netherworld, weaving a rope of straw. As depicted in the picture by Polygnotos, standing behind him is his donkey which eats the rope as fast as it is made.

 This article incorporates text from a publication now in the public domain: Smith, William, ed. (1870). "Ocnus". Dictionary of Greek and Roman Biography and Mythology. 

...
Wikipedia