Once upon a time, there was a lighthouse, with a lighthouse keeper. It was far out in the sea, a simple tower perched upon a few rocks, battered by the winds and the waves. It was a lonely life, but our keeper found in it both its solace and his contentment. He spent his days trimming the wicks of the main lights, replenishing the fuel, rewinding the clockworks and cleaning the windows, his nights manning the main light under the calm moon. Our keeper was a handyman who had never married, and his only link to the mainland was a boat who came every month to deliver groceries and news from the world.

One evening, the keeper came out of the lighthouse and found something stranded on the northern shore. He shone his lantern, only to reveal a beast, a serpent-like monster with a horned-nose and a mouth wide open on hundred of sharp teeth. It was big as a horse, and covered in scales radiating green, blue and purple. The keeper stopped to take it in, and the creature opened its eyes. They were huge, dark and glittering with bronze speckles. The monster said, in a deep, guttural voice: “I am Bakunawa, the sea-serpent, and I was almost killed. I need your help, and if you help me I will not eat you.”

The keeper asked, perplexed: “How can I help you?” and the monster replied “Bring me water, and feed me light.” The keeper immediately took a cup of rainwater from his reservoir, and lit up a few wicks from his stock. The monster gulped it down, the flame travelling down its long and sinuous body.

In the day, the monster would sleep; at night, it would demand the same things, more light and more water. The keeper never failed, and Bakunawa never ate him. exchanged a few words, enough for the keeper to piece the story together - Bakunawa had been defeated when trying to rescue his sister from a shipping boat. The encounter had left the sea serpent depleted, and close to death. Now, the keeper nursed him back to life, and it became obvious that Bakunawa was gaining strength: he was growing. Day after day, he grew to the size of a carriage, and then a small house, and again to almost as tall as the lighthouse itself. In a few days, it was sprawled out on the whole space available on the small rock.

One night, a storm broke out at sea. The keeper stayed in and manoeuvred the light to make sure the boats out there would be safe, and when he took a moment to go out and check on the monster, he witnessed a peculiar spectacle: with each lightning, the monster seemed to expand and strengthen, but with each roll of thunder he would spasm and writhe as if it were painful.

A couple days after the storm, the keeper came out at night with the wicks, but the monster was nowhere to be found. As he proceeded to walk back, a sudden parting of the sea revealed Bakunawa, now huge, his speckled eyes taller than his entire size the day he was stranded ashore: “You helped me, keeper, and I will keep my promise to spare you. But your kind killed my sister, and for that reason I will steal the moon.” With a powerful leap, the gigantic snake flew towards the full moon, opened his jaw, and closed it on the giant white orb.

At once, darkness fell on the sea. The keeper could barely make out the surroundings thanks to the light of the lighthouse. He thought of the ships out at sea, and knew he had to act fast. He climbed up the stairs to the lantern room, grabbing tools that he immediately began to hit the metal parts of the room with, making a cacophony of noises that resonated into the black night.

With a gurgling noise, Bakunawa writhed and buckled, with more and more frenzy - and finally spit it back out, falling back in the bubbling sea.

The secret to beating the monster was shared for generations of lighthouse keepers, and the sea monster has kept his promise to not eat them - so that, every time the moon is in danger, there is someone to play loud music and sounds to make the serpent spit it back out.