The phrase comes from William Shakespeare's Hamlet, where Horatio speaks 'Good night, sweet prince, and flights of angels sing thee to thy rest' over the dying Hamlet. Shortened online to goodnight sweet prince, the line became a standard ironic caption and audio reaction for deaths, eliminations and fond farewells. Forums and video edits paired it with screenshots and clips of fallen characters, and its sincere, literary grief made ordinary losses funnier by contrast, keeping it in use as a respectful but teasing sendoff.