Light is one of the most important elements in Middle Earth, because it banishes darkness, and can harm all of the evil creatures and beings that dwell in shadow. This love of light that is shared by elves and men alike, stems from long before the Children of Illuvatar were awoken, long before they were even conceptualized within Eru’s mind. It stems from the two Trees of Valinor, created by the Ainur Yavanna, which gave off such an ethereal beauty in their silver and gold illuminations that the light fused with the looker's soul and kept them pure and content ever after.
But as light is the enemy of dark things, there were those in the world who wanted to destroy the light of the Trees, taint it and ruin it so that no others could share in its joy. This, ultimately, is the goal of the evil lords in Middle Earth, from Melkor to Sauron, from the Witch King of Angmar right down to Saruman the once white wizard. They wish to eradicate all that is good and brings hope, and replace it with the hollow void that exists inside themselves. And this is exactly what was achieved when Melkor managed to drain the light of the Trees of Valinor, and ruin their beauty forever. But how could the evil lord, powerful that he was, eradicate such a loved and well-protected treasure?
He sought out a creature that is the exact opposite of life and love and joy, a creature who feeds off light and has an insatiable need to devour everything that gleams and glows. The creature was called Ungoliant (Shelob's mother) who at first existed as a formless entity of pure darkness and shadowy death, but she eventually came to take on the form of a monstrous and grotesque spider, at the bidding of Melkor, who promised her that if she helped him to taint Valinor, he would let her gorge herself to her hearts content, and eat up all the light and joy that was spilled from the ruins of his once loved home. ‘In a ravine she lived, and took shape as a spider of monstrous form, weaving her black webs in a cleft of the mountains. There she sucked up all light that she could find, and spun it forth again in dark nets of strangling gloom, until no light more could come to her abode; and she was famished.’
They journeyed together to the lands of the Ainur, who were unsuspecting of just how far their brother’s cruelty and malice could reach. They were fully aware at this time that Melkor had gone rogue, and that he posed a threat, but they didn’t dream the full extent of the damage and the heartache that he would cause them. The only one who had a small inkling of it was Feanor, who managed to save a small slither of the light of the Trees in his three precious Silmarils. But whilst all the others were at a feasting celebration of the bounty of Eru, their creator, Melkor and Ungoliant snuck up from the hills and attacked Yavanna’s dearest creation:
‘The Unlight of Ungoliant rose up even to the roots of the Trees, and Melkor sprang upon the mound; and with hi black spear wounded them deep, and their sap poured forth as it were their blood, and was spilled upon the ground. But Ungoliant sucked it up, and going then from tree to tree she set her black beak to their wounds, till they were drained; and the poison of death that was in her went into their tissues and withered them, root, branch and leaf, and they died. And still she thirsted, and going to the Wells of Varda she drank them dry; but Ungoliant belched forth black vapours as she drank, and swelled to a shape so vast and hideous that even Melkor was afraid.’
Ungoliants filthy shadow stretched so far and wide that the Valar realized what terrible fate had befallen the Trees, and they wept for the loss. Yavanna broke her heart bitterly, and begged for Feanor to let her use the light that he had stored in the Silmarils to bring the trees back, but they were foiled yet again, for Melkor had already anticipated this, and had stolen the three precious gems from their safekeeping. Thus the Ainur lost two great creations that day, of which the likes could never be remade or brought back to being, and their hatred of Melkor grew so strong that they renamed him Morgoth, and cast him from their love forever. The Silmarillion is about their quest to get the three precious gems back, and heal some of the wounds that Melkor dealt them that day.