*************after several years*******************************

First curse:

As Parshurama only taught to Brahmins, Karna appeared before him as a Brahmin because of the fear of rejection. Parashurama accepted him and trained him to such a point that he declared Karna to be equal to himself in the art of warfare and archery. On a day towards the end of his training, Karna happened to offer Parashurama his lap so his guru could rest his head and take a nap. But while Parashurama was asleep, a scorpion stung Karna's thigh. Despite the pain, Karna did not move, so as not to disturb his guru. In some versions, Lord Indra became afraid of the fighting prowess of Karna and he himself took the form of a scorpion and stung Karna's thigh in order to benefit his son Arjun. With blood oozing from his wound, Parashurama woke up at once deduced that Karna was not a Brahmin. Parashurama, who had sworn to teach Brahmins only, laid curse upon Karna that he would forget all the knowledge required to wield the divine weapon Brahmanda astra.

Upon Karna's pleading, Parshurama relented and modified his curse, saying that Karna would only lose the knowledge when he needed it most when fighting against an equal warrior. To bypass the given curse, Parashurama gave Karna his personal celestial weapon called Bhargavastra which no one else possessed, for being such a diligent student. Repenting over the curse and in order to nullify it, Parashurama gave his personal bow called Vijaya to Karna for being ever victorious in battle and blessed Karna,

"On earth, no Kshatriya will be equal to you in battle"

Parashurama also gave his chariot which was made in silver with tiger skins and multiple weapons such as axle, mace and sword in it.

Second Curse:

Karna was also cursed by a Brahmin for killing his cow while practising his skills with bow and arrows. The Brahmin got angry and cursed him that he would become helpless and die in the same way the innocent cow had become, by his chariot wheels getting stuck in the ground.

Another version of the second curse:

Karna once encountered a child who was crying over her pot of spiltghee. On asking her the reason for her dismay, she stated that she feared that her stepmother would be angry over her carelessness. Refusing to take new ghee from Karna, the child insisted that she wanted the same ghee. Taking pity on her, Karna took the soil mixed with ghee in his fist and squeezed it with all his might, so that the ghee dripped back into the pot. During this process, Karna heard the agonized voice of a woman. When he opened his fist, he realized that the voice was that of Bhoomidevi, the Earth goddess. She furiously chastised Karna for inflicting enormous pain on Mother Earth for the sake of a mere child and cursed him that at a very crucial moment in battle, his chariot wheel would be trapped as tightly as he had held that fistful of soil and die helplessly.