Also called
Ooharazu, the immense
monkey form of the
Saiyans of
DragonBall.
When a Saiyan that hasn`t had his tail removed sees the
full moon, he undergoes a transformation... He becomes an immense (30-40 meters tall), red-eyed monkey-like monster. His
power level is multiplied by ten (usually enough to top any fighter in the area) and he gains a special attack, the ability to shoot a ray of energy from his mouth. Unfortunately, the Saiyan also becomes uncontrollable. The Saiyan only returns to normal after the moon vanishes or if his tail is cut or torn off.
Of course, this power is very dangerous. By the end of the
Dragonball Z series, all Saiyans have lost their tails (Can't say that for
Dragonball GT, though), favoring the safer
Super Saiyan transform.