Under Drona's tutelage, the Kauravas and the Pandavas, along with the princes of Hastinapura's allies and vassals, learned weaponry. Arjuna became Drona's favorite and most accomplished pupil; specifically, he became a master in using the bow and the arrow. In a famous incident, Drona deemed that out of all his students, even his own son Ashwatthama, none but Arjuna had the steadfast focus to shoot the eye of a bird on a tree; he was proven right. One day, on being questioned by Ashwatthama; why was Drona being partial to Arjuna, Drona replied Arjuna that he was not being partial to anyone but his favourite was Arjuna. His intention was very clear that he loved Arjuna but didn't ill-treat anyone. He ordered Ashwatthama to assemble with all of his students at a nearby lake that evening. They gathered as directed and found Drona taking a bath. Suddenly a crocodile appeared in the lake and began to attack Drona. Nobody dared to enter the lake except Arjuna, who jumped into the water and began to attack the mighty crocodile with his bare hands. Suddenly the crocodile disappeared. Drona explained that the crocodile was just an illusion he had created to test all the princes and Ashwatthama. Drona scolded that no one was ready to save their teacher except Arjuna. Thus Drona proudly declared that Arjuna was his favourite and pet student.