Karn's Curse and Challenge
Karn wished to train under Lord Parashuram. As the adopted son of the charioteer Adhirath, Karn was a Kshatriya. But Parashuram trained only Brahmins; he hated Kshatriyas with a vengeance as they killed his father, Rishi Jamadagni. So Karn disguised himself as a Brahmin to become Parashuram's student. He was an excellent student and eventually became an expert archer.
One day, while Parashuram was resting asleep on Karn's lap, Indra, the king of the gods, transformed into a bee and stung Karn's thigh. Karn began to bleed but didn't move a muscle because he didn't want to awaken his teacher. But when Parashuram's clothes became soaked with blood, he awoke with a start. Since a Brahmin could not possibly withstand such intense pain, Parashuram realized that Karn was a Kshatriya in disguise. Furious, he cursed Karn:
"You will forget my teachings when you need them the most."
The Kuru princes' education was drawing to a close. Dron wished to organize a grand parade for his students to showcase their skills. The elders of the Kuru clan gave their permission, and a stadium was prepared. Astrologers were enlisted to determine an auspicious time for conducting the parade.
On the scheduled day, Dron and his students reached the stadium. The audience was excited to watch chariot riding, horse riding, and mace fighting. Vidur satisfied the blind Dhritarashtra's curiosity by describing the events to him. The mock mace fight between Bheem and Duryodhan quickly escalated into an actual battle, and at Dron's behest, Ashwatthama separated the two.
When Arjun entered the arena, people watched with bated breath. His archery skills were outstanding, and every arrow of his hit its target. He used a fire arrow to light a fire and, with a second arrow, extinguished the fire. Another arrow of his caused the sky to become covered with black clouds. When the audience was shocked, he used a wind arrow to disperse the clouds. He also performed various other extraordinary feats.
After this, a youth wearing golden earrings and armor entered the arena. He announced that he could replicate all the archery feats previously performed. After displaying his prowess, he shouted, "I challenge Arjun to a duel."
The new entrant was none other than Karn. As Arjun accepted his challenge, Kripacharya stood up and said, "Young man, you have challenged Prince Arjun of the Kuru clan. He is the youngest son of Pritha and is also known as Parth. Please state your royal lineage as well. A prince will not accept a challenge from a commoner."