The Unus Annus Annual Costume Contest

Summary
Mark and Ethan compete against each other in a costume contest in scary, sexy, sad, cursed, offensive, funny, and cute categories. As Mark is declared the winner, Ethan is forced to stay behind by himself at the Halloween-themed house.

Trivia

 * The opening and ending scenes feature animated sequences by UltraMarine.
 * The intro sees Mark and Ethan walking up to the screen in tandem with its Unus Annus chant, as they break the fourth wall by pulling down a black cover over the title sequence.
 * The outro sees Mark and Ethan's Unus Annus silhouettes swinging a pendulum-like timer towards one another. As Mark catches it, the clock turns into a skull, followed by a rose with its petals blowing in the wind. As one lands on a body of water, it transforms again into Ethan leaning against a scythe. The final transformation has the scythe bearer turn into the Unus Annus hourglass, as the scene zooms out to show the device lying in the hands of Mark's silhouette, concluding the video.