The Joker
The Joker's persistence defies medical and narrative logic. He has survived encounters with superhuman combatants, apparent deaths that would permanently conclude any ordinary existence, and physical trauma that should have ended his career decades ago. Some theorists suggest his meta-narrative importance grants immunity from permanent elimination.
Chemical alteration of his physiology may provide enhanced recovery capabilities, though documentation remains inconsistent across source materials.
The Moon
The Moon has endured 4.5 billion years of cosmic bombardment, its cratered surface a testament to impacts that would have vapourised continents on Earth. The South Pole-Aitken basin, spanning 2,500 kilometres, represents an impact that would have sterilised any inhabited world, yet the Moon persists.
It has witnessed the formation of Earth's oceans, the emergence of life, and will continue orbiting long after humanity's extinction. Its durability operates on geological timescales that render human concepts of permanence meaningless.