The Walker

The Walker is both an attack and a ,some what to a point, living being. It wanders planets looking for energy to drain or that someone will provide it with energy. It can not be harmed by physical attacks, and any and all energy attacks it absorbs.

Legend
Legend has it, that The Walker was originaly a powerful being who absorbed to much power and became his own attack.

It is actually an energy that was so strong that it came to life, do to all the life force it had. Meaning it had more life force in it then the Universal Spirit Bomb.

History
Goku and Vegeta took it on after the Shadow Dragons attack the Earth, 5 years after actually. It did not cause any trouble on Earth, but Vegeta was afraid that it was going t destroy Earth and did everything he could to stop it. Goku tried figuing out what it wanted. When he tried making a mental connection with it, it actually had one and told him that it only wanted energy, but did not want to kill or force the energy from a being even though it could. Everyone on Earth gave it some energy and it was very thankful and left. It is said to rest on Namke because of how peaceful they are.