Cell

The most dangerous of all Dr. Gero's creations, Cell, was created in Dr. Gero's lab as a genetic experiment. He comes complete with a self-destruct feature, a scorpion-like tail that opens up to absorb the energy of his opponents, and instructions to wreak revenge on the Androids which caused Dr. Gero's downfall. Cell contains the DNA of the mightiest warriors of the universe including Goku, Piccolo and Vegeta. Possessing the DNA of these great warriors, Cell is able to fight with their attacks. With these great forces combined Cell is an almost invincible being. One of his greatest advantages is being able to regenerate himself at any given time from even the smallest component of himself. We discover this in Dragon Ball Z when the good guys believe Cell is destroyed, only to find out that a brain cell has survived. From this cell, Cell regenerates himself and appears out of nowhere once again threatening Earth. One of Cell's only weak points is that his energy is finite. He gains power by draining the energy of his enemies using his scorpion-like tail to do so. Cell has three forms: the imperfect form in which we first see him, the second stage of Cell, and the final or Perfect Cell. He reaches Cell Stage Two after absorbing Android 17. When Android 18 is consumed, Cell changes into his third and most powerful form: Perfect Cell. Cell can and does create smaller versions of himself. Cell eventually dies from a one handed Kamehameha done by a very injured Gohan, and a little help from Vegeta.