Dark Evolution is a type of transformation that a Demon God with high magic power can force upon a chosen target.
A Demon God is capable of causing a warrior to undergo a dark evolution by adding their Demon God power with their target's "kiri", a soul's energy.
Mechikabura transformed King Vegeta into the personification of his magic power, causing King Vegeta to undergo a dark evolution into a form that turns his hair black with one red spike and gives him red and black eyes.
Video Game Appearances
In Dragon Ball Online, Cell takes on his Cell-X dark evolution through unknown means after his revival.