From the Folklore of Uttarakhand
A certain Brahman, having no children, went to a Jogi (ascetic) and implored him to bless him with progeny. The latter, after giving him some wonderful medicinal root, claimed the first-born for his disciple. The Brahman agreed to fulfil the condition, as soon as he was given the sons so promised. The Jogi then departed.
The man in due time got two sons who grew to manhood. The same Jogi came to the man and asked for the elder son, who was readily given him. But the man requested the ascetic to take his younger son also for a training under him. The latter granted his request. So the Jogi took both the sons of the man with him, and instead of teaching his art to both alike excluded the younger from the boon, and began to train the elder one, supposing him to be his own disciple, inside a room which was shut against the younger one. But the latter, being smart and inquisitive, gave his ears and mind to what was taught inside to his brother, by stealthily standing close to the door, which was shut, and attentively hearing what was taught to his brother inside.
Once the Fakir gave each a wooden bowl to be oiled. The elder one begged oil and clarified butter from door to door, for the purpose and got it a little oiled; but the younger one, on the contrary, contrived a better plan for so doing. He purchased bowlful of oil on credit, and returned it next day on the plea of its being of a bad quality and so got his bowl fully greased in the process. Finding the younger one more ingenious than the other, the ascetic drove him from his house.
The younger lad came to his father and told him that he would metamorphose himself into a nice mare which he would sell to any one for 500 Rupees but he should not part with the bridle, otherwise he would come to great troubles. When the boy had transformed himself into a mare, his father took him to market for sale. The very same ascetic, who knew him to be the boy, purchased it. He made it over to his disciple (the elder brother) with instructions that she should get fodder and water at home, that is not be taken out for the purpose. The disciple acted on the advice of his tutor for a considerable time.
One day it so happened that the disciple of the ascetic, forgetting the counsel of his instructor, took the advice of his tutor for a considerable time. One day it so happened that the disciple of the ascetic, forgetting the counsel of his instructor, took the mare to a river, so that she might drink water. No sooner had the mare touched the water of the river than she disappeared, turning into a fish.
On hearing this from his follower the ascetic assumed the form of a fisherman, to catch the counterfeited fish. When the fisherman was about to catch the fish, it turned itself into a bee, the fisherman became a hornet to kill it. The bee then transformed itself into one of the pearls in the wreath worn by the daughter of the king of the country. On feeling some sensation, the princess threw off her garland on the pavement of her palace. No sooner was this done than the ascetic having metamorphosed himself into a cock began to eat up the scattered pearls (with a view to kill the boy). Just before the boy was about to be devoured by his adversary he transformed himself into a cat, and killed the cock, his enemy.
Source:
Himalayan Folklore: Kumaon and West Nepal, E.S. Oakley and Tara Dutt Gairola, 1935
For the Serbian version of this same tale, see the following:
Kotharian Lightning 