Having received boons from the gods, Hanuman grew up to be a strong and fearless monkey. He was also mischievous! He would tease the sages of the forest, breaking their pots, tearing up their clothes and interfering with their sacrifices.
Finally the sages cursed Hanuman. "You will forget all your powers!" they shouted at him, and Hanuman no longer remembered the boons he had received.
It was not until he heard the words of King Jambavan years later, on the shore of the sea, that he remembered the supernatural abilities that allowed him to jump all the way to Lanka.
Inspired by: The Ramayana (Uttara Kanda, 36).
Notes: Jambavan reminds Hanuman of the story of his birth and great powers in Sarga 66 of the Kishkindha Kanda. Even today, mischievous Hanuman Langur monkeys cause all kinds of problems, especially in the cities like Delhi: Langurs of Delhi.