Monday
Monday possesses immortality in the truest sense of the term. This temporal construct has persisted through the rise and fall of empires, the extinction of species, and the complete transformation of human civilisation. Barring the collapse of the Gregorian calendar system, Monday will continue its weekly visitations indefinitely.
Projections suggest Monday will outlast human civilisation itself. Even should Homo sapiens vanish entirely, the concept of Monday will persist in any documentation that survives, a testament to the concept's extraordinary durability.
Spider-Man
Spider-Man's tenure of 63 years represents considerable longevity by entertainment standards, exceeding the lifespan of most fictional characters. The property shows no signs of declining relevance, with recent multiverse films achieving record-breaking revenues.
However, intellectual property remains subject to cultural shifts that temporal concepts avoid. While Spider-Man currently thrives, the history of popular culture is littered with once-dominant characters now relegated to nostalgic obscurity. Eternal relevance cannot be guaranteed.