Lough na Suil and the end of the Battle of Moytura
Many of the sites around Moytura have been woven into the story, and none more so than Lough na Suil, the Lake of the Eye. During the Battle, Lugh was placed sitting on the neolithic cairn which bears his name, Shee Lugh. From that vantage point, he followed the events as they unfolded.
Balor of the Strong Blows, grandfather of Lugh, was on the field and none could stand before the power of his baleful eye. From his vantage Lugh saw Nuada of the Silver Arm and Macha destroyed by Balor, and he leapt down from Shee Lugh and entered the fray.
The place where Nuada and Macha were slain is marked by the Labby Rock, a massive neolithic dolmen with a capstone said to weigh some 70 tons. Lugh bounded on down the hill, chanting a battle spell, and confronted his grandfather, calling out a challenge.
This archetypal story has been told many times by many different cultures. It was used as the basis for the first Star Wars movie, where Balor of the Evil Eye is represented by Darth Vader, and his grandson Lugh of the Long Arm is the model for Luke Skywalker. Indeed, in the story the Battle was fought using the Sword of Light, one of the four treasures of the Tuatha Dé Danann.
The climax of the Second Battle arrives when Lugh hurls his spear or his slingstone through the Evil Eye of his grandfather; Luke Skywalker fires his photon torpedo into the exhaust vent of the Death Star; and Isildur cuts the One Ring from Sauron's hand.
The grandfather/grandson mythic archetype is also explored in the novel Dune by Frank Herbert. A very fine retelling of the story is found in the Lyonesse novels by Jack Vance, a friend of Frank Herbert.
Back at Moytura, when Lugh destroys the Evil Eye, his grandfather falls dead, and the baneful power of the Eye kills a number of Formorian warriors. The flaming Eye rolls down the hill until it comes to a stop, where it burns a hole in the ground. Finally the Eye meets water, and the fire is quenched, and Lough na Suil is formed in the process.