Nebula is a fanon element created by Sensei Purplebrick. You are welcome to use it and modify it for your OCs, but please list your modifications separately.
According to legend, the First Spinjitzu Master gave this element to one of his allies, but seeing its power and unpredictability, regretted this action. He made the first Master of Nebula promise not to tell his offspring of the power, in hopes they would never know they had it. However, a few managed to discover it. Nebula, like the real thing, looks like clouds. These clouds are red mixed with dark purple. Nebula is capable of disintegrating almost anything it touches. It can absorb most other elements as well. A human (or animal) hit by a small amount of it may not disintegrate but much damage is done, often killing the person.
Its only weaknesses are the Energy element, which neutralizes it, and the fanon element Life, which upon contact with it explodes. Strong winds can also blow it around.
A ninja wearing a dark, reddish purple gi is likely to be a master of Nebula.