Indra, the king of the Devas, had a special affection towards Arjuna, one of the five Pandava’s brothers, because the latter had been born to Pandava’s' mother Kunti by his (Indra's) own blessings.

Indra knew that Pandava’s had to wage war against their cousins, the Kauravas led by Prince Duryodhana, and that Karna would be the right hand man of the prince. He decide that Karna had to be vanquished so a to ward off danger to Arjuna.

Indra pondered over how to realize this objective. Karna had completed his training from Parashurama success fully; who can match him now? Indra had to think of some incident wherein the Guru's wrath would descend upon his disciple. He assumed the form of a diamond-sharp insect and began bite into the flesh of Karna's lap. Can anybody withstand such severe torture for long? But Karna was worried that even the slightest dislodging of his lap would disturb the Guru' sleep. He suffered all the severe pain of the insect's biting with tenacity His lap began to bleed, and as the floor got wet with blood, Parashurarna suddenly woke up. And what did he see? His disciple is sifting quiet, while his lap was bleeding He was suffering such great pain silently

A doubt confronted Parashurama.This boy is certainly not a Brahmin, for only a Kshatriya could suffer this pain in silence. The boy must be a Kshatriya; he had deceived him and learnt archery.