Sīhacamma Jātaka (No.189)
Once a merchant used to go about hawking goods, his pack carried by a donkey. After the day’s work he would throw a lion’s skin over the donkey and let him loose in the fields. The farmers, taking him for a lion, dared not stop him eating their crops. However, one day they summoned up courage and armed themselves, and approached the animal with great uproar. The donkey, frightened to death, heehawed. The farmers cudgeled him to death.
The story was told in reference to Kokālika, who is identified with the donkey (J.ii.109 f).