Dracula
Dracula's immortality represents a significant competitive advantage in any durability assessment. The Count has maintained operational status for over five centuries according to canonical sources, demonstrating remarkable persistence despite numerous documented termination attempts.
His regenerative capabilities allow recovery from wounds that would prove fatal to conventional organisms. However, this immortality remains contingent—a well-placed stake, sufficient sunlight exposure, or decapitation can terminate even the most ancient vampire. Dracula's longevity, whilst impressive, carries an asterisk of vulnerability.
Monday
Monday's temporal existence predates any individual vampire by several millennia. The seven-day week emerged in ancient Babylon approximately 4,000 years ago, meaning Monday has been draining human enthusiasm since before Dracula's great-great-grandparents drew breath.
More significantly, Monday cannot be destroyed by conventional or unconventional means. No stake exists that can pierce a day of the week. No sunlight can banish a calendrical concept. Monday will persist until humanity abandons the weekly cycle entirely—an eventuality so remote as to approach functional immortality that surpasses even vampiric standards.