The line comes from J. R. R. Tolkien's The Lord of the Rings and its film adaptation, where Gandalf promises to return at dawn on the fifth day before riding to aid Rohan at Helm's Deep. The German dubbed version, 'Erwartet mein Kommen beim ersten Licht des fünften Tages,' became the form shared on soundboards and in German-speaking meme edits. Its mix of prophecy, loyalty and last-minute rescue has kept it popular for comeback and entrance jokes long after the films' release.