The 'You Shall Not Pass' meme originates from the 2001 blockbuster 'The Lord of the Rings: The Fellowship of the Ring.' In a climactic scene, the wizard Gandalf, played by Sir Ian McKellen, stands his ground against a monstrous Balrog on the Bridge of Khazad-dûm to protect his fellowship. While the original book line was slightly different ('You cannot pass'), the movie version became an instant cultural phenomenon. On the internet, this meme serves as the ultimate symbol of defiance and gatekeeping. It is frequently used to mock strict rules, firewall errors, stubborn pets, or any situation where progress is firmly halted by an immovable force.