Dragon Ball is known for its over-the-top transformations. Whether it’s Goku’s iconic super saiyan form, or Cell's transformation to perfection, Dragon Ball's most powerful warriors always gain power by transforming. While some transformations are built up to and foreshadowed quite well, others can be almost completely random in their appearance.
Source：https://www.cbr.com/10-dragon-ball-transformations-that-came-out-of-nowhere/
