There is a legend that the death of Koshchei the immortal lies in a needle, a needle in an egg, etc. There is a belief that if you get a needle, you can gain immortality

Your sister is sick, so you went looking for the needle, but once you got it, you were trapped. And now Koschey was sitting in front of you, burning with his eyes, and on the sides of him were his two sons "Poor greedy human" man growled