Physical Immortality

Tuck Everlasting

In the novel Tuck Everlasting, a family is made physically immortal by drinking water from a magical spring. They are trapped at the same age forever and are invulnerable. They are hated by the ordinary people who knew them and are forced to watch as everything they cherish grows old and dies.

Vampire: The Requiem

The the roleplaying game Vampire: The Requiem, published by White Wolf Publishing, Inc., vampire possess a form of immortality, known as undeath, wherein their bodies are absent of all life functions (such as breathing and a heartbeat). They have theorectically inifinite lifespans (and can even survive unprotected in the vacuum of space and under the crushing depths of the ocean), but they can be killed with enough damage. Though they are also forced to watch as everything they knew in life withers away and are they are unable to adapt to the changing eras of history. Because they are fallible predators, their humanity also begins to deteriorate, and a few become mindless/insane monsters called Draugr (also known as Revenants) as a result of losing all concept of being human. Such ravening monsters are always hunted down by other vampires, to prevent humans from learning of the existence of vampires.

Deep One Hybrids

In the Cthulhu Mythos created by H. P. Lovecraft, there is an race of "Fish-Men" known as Deep Ones. They stop aging after reaching adulthood and can breed with humans to birth offspring with this "eternal youth." Though this is a faustian bargain, as after reaching the age of 20, the Deep One Hybrids undergo a transformation from normal humans into hideous Deep Ones. They also loose all concept of humanity and morality and go to live in the ocean with the Deep Ones and to worship the undersea deity Cthulhu, the Lord of Madness.

Death Wish

The Star Trek: Voyager episode Death Wish explored in depth the existance of the omnipotent, immortal and omniscient aliens Q. It is learned in that episode that the aliens were originally human-like, and somehow evolved into their current state long ago. With their new-found powers, the Q set out to fully explore, experience and understand the universe. Afterwards, the Q had nothing left to do or say, and now they simply sit out eternity in their realm. As one Q explained, you can only experience the universe so many times before it gets boring.