Hanuman was the son of Vayu, the god of the wind, and Anjana, a celestial nymph. You’re probably wondering how the son of the wind god and a nymph turned out to be a monkey. The answer is that Anjana once angered a sage who cursed her to be born as a monkey. When the nymph begged for pardon, the sage calmed down and said that she would regain her original form after she bore a son who would win great renown.
Even as a child, Hanuman had great powers. One morning, he saw the sun rising and thought it was a great yellow ball. He decided to get hold of it so that he could play with it. Indra, the king of gods, saw Hanuman leap into the sky and wanted to stop him. And how did he do that? He threw his weapon, the Vajra (thunderbolt) at the child. Hanuman fell to earth, wounded.
The gods knew they had to placate Vayu. So, they offered the baby a multitude of boons. Brahma said that no weapon would ever hurt Hanuman and that he would be able to change his form at will and travel wherever he chose. Indra’s boon was that the Vajra would no longer hurt the child and that his body would be stronger than the weapon. Varuna, the god of the ocean, offered him protection from water.
Agni, the god of fire, blessed him with immunity to fire. Surya, the sun god, gave him the power to change the size of his body. Yama blessed him with good health and immortality. Vishwakarma, the divine architect, offered a boon that Hanuman would be safe from all objects of his creation.