The power to be immortal by not staying dead. Variation of Immortality.
The user is immortal in the sense that when they do die, they won't stay dead. This could be the result of instant resurrection, being reborn, transferring one's mind/soul into a clone, etc. Unlike other forms of immortality they can still die from any cause, like physical trauma, disease or simply aging, but the user will always come back to life.
The most famous quality of ajins (Ajin: Demi-Human) is that they never stay dead.
Humanoid Cylons (Battlestar Galactica) continuously resurrect in new bodies upon their current bodies' deaths.
After being killed by the Daleks and then resurected by Rose Tyler, Captain Jack Harkness (Doctor Who) gained the abillity to come back from death
After becoming a spirit, if Victor's (Hatchet) body is somehow destroyed or "killed", he'll come back because he has to repeat the night he died for eternity until he finds his father.
Mr. Immortal (Marvel Comics) is a Homo Supreme, having evolved beyond death, he will always come back to life no matter how many times he is killed
Nathan Young (Misfits) will always come back to life upon death, no matter how long it takes.
Snow White (Valkyrie Crusade) is an absolute immortal in that while she can die, she NEVER can stay dead, and will always comes back to life, not matter how she dies.
Phantom (Marchen Awakens Romance) cannot stay dead as long as he has the Zombie Tattoo. It’ll take a few years, but Phantom will indeed be eventually resurrected.
After being killed and reconstructed by the Mysterons, Captain Scarlet (Captain Scarlet and the Mysterons) gained the Mysteron power of "Retrometabolism" which allows him to heal from serious injuries and return from death.
Resurrection Man's (DC Comics) power is the ability to die and resurrect with a random power, usually associated somehow with his death.
As the central hive mind of the parasitic Flood, the Gravemind (Halo) can keep resurrecting itself ad infinitum as long as even a single Flood spore still exists to infect other creatures.