Unus Annus was a transformative YouTube project launched by Mark Fischbach (Markiplier) and Ethan Nestor (CrankGameplays) on November 15, 2019, with a strict expiration date of exactly one year. The channel's name, Latin for 'One Year,' and its slogan 'Memento Mori' served as constant reminders of mortality and the importance of living in the moment. Every video was deleted after 365 days, making the memes born from this era both nostalgic and exclusive to those who 'were there.' Today, Unus Annus memes typically feature the iconic black-and-white spiral, the digital countdown clock, or the contrasting suits of the two hosts, representing the fleeting nature of time and the chaotic energy of their daily challenges.