There are many versions of The Brahmin and The Mongoose, but the most traditional one is the following, taken and translated from and Indian script (although I have deleted some parts, as the story I found was a bit long);
There was once a Brahman named Godly who lived with his wife, their single son, and a mungoose. And the mother loved little ones, she cared for the mungoose also like a son, giving him the same care as their child. But she did not trust him, for she thought: “A mungoose is a nasty kind of creature. He might hurt my boy.”
One day she tucked her son in bed, took a waterjar, and said to her husband: “Now, I am going for water. You must protect the boy from the mungoose.” But when she was gone, the Brahman went off somewhere, leaving the house empty.
While he was gone, a black snake issued from his hole and, as fate would have it, crawled toward the baby’s cradle. But the mungoose, feeling him to be a natural enemy, and fearing for the life of his baby brother, fell upon the vicious serpent halfway, joined battle with him, tore him to bits, and tossed the pieces far and wide. Then, delighted with his own heroism, he ran, blood trickling from his mouth, to meet the mother; for he wished to show what he had done.
But when the mother saw him coming, saw his bloody mouth and his excitement, she feared that the villain must have eaten her baby boy, and without thinking twice, she angrily dropped the water-jar upon him, which killed him the moment that it struck. There she left him without a second thought, and hurried home, where she found the baby safe and sound, and near the cradle a great black snake, torn to bits.
I first read about The Brahman and The Mongoose by Sangu Mandana, in her book The Lost Girl. It might just be me, but I found the story so sad that I had to share it.
Don't be so quick to judge.