The Fellowship of the Ring travelled through Moria on the quest to destroy the One Ring in Mount Doom. They were attacked in the Chamber of Mazarbul by Orcs. The Fellowship fled through a side door, but when the wizard Gandalf the Grey tried to place a shutting spell on the door to block the pursuit behind them, the Balrog entered the chamber on the other side and cast a terrible counterspell. Gandalf spoke a word of Command to stay the door, but the door shattered and the chamber collapsed. Gandalf was severely weakened by this encounter. The company fled with him, but the Orcs and the Balrog, taking a different route, caught up with them at the Bridge of Khazad-dûm. The Elf Legolas instantly recognized the Balrog and Gandalf tried to hold the bridge against it. As Gandalf faced the Balrog, he proclaimed, You cannot pass, flame of Udûn!, and broke the bridge beneath the Balrog. As it fell, the Balrog wrapped its whip about Gandalf's knees, dragging him to the brink. As the Fellowship looked on in horror, Gandalf cried Fly, you fools! and plunged into the darkness below.