of the details that started to provoke a great fuss in Dragon Ball was
the tail of the little Son Goku. At first it seemed just only a special
detail that Toriyama used to give Goku a distinctive mark, but soon we
discovered that this tail concealed a secret!
When Goku and company are taken prisoner by Pilaf, our hero tells his
friends that his grandpa was killed by a creature appearing during full-moon
nights. Bulma and Yamcha think that's an old legend, but when Goku says
that his granpa had forbidden him to look at full moon, they both start
to suspect about him and... his tail.
Then Goku looks at the full moon and soon becomes unconscious and turns
a giant ape, without his reason and control on himself and with an unbelievable
destructive power. Goku stops to look like a giant ape and returns normal
when they cut his tail off and, when he wakes up, he doesn't remember
This same transformation happens another time during the final match of
20th Tenkaichi Budokai, when Muten Roshi, disguised himself as Jackie
Chun, decides to destroy the Moon to avoid this situation to happen again
in the future.
A few years after Gohan's birth, here is Raditz coming
on Earth and they discover that the tail is a Saiya-jin distinctive mark
and the source of Saiyans power. So Goku is a Saiya-jin too, just
like his brother! When Goku and Raditz die, Piccolo, aware about the next
arrival of other Saiyans, decides to personally train Gohan and it's revealed
that also the child "suffers" from the same problem of his father:
when he looks at full moon, Gohan turns a giant ape having no self-control
Finally all the truth about this transformation is revealed when Vegeta
and Nappa come on Earth and fight against Goku. Vegeta, realizing Goku's
unexpected strengthening, decides to use his last resource: the transformation
But Piccolo had already destroyed the Moon to stop Gohan's
fury, so also Vegeta should not be able to turn... Well, he doesn't waste
any time, no matter where they've put the moon for this planet, he can
make due without it... Vegeta tells Goku that the absence of the Moon
will not prevent him from turning and then proceeds to explain that :
"The Moonlight indeed is the reflex of ray of Sunlight (in fact we
know that the Moon shines with reflected light!)... but only when Sunlight
is reflexed in the Moon, the Brute (Burutsu) wave forms... And if the
rays of Sunlight are reflected in the full Moon, the power of the Brute
wave reaches 17 million zenos... When eyes absorb this wave it's possible
to transform... Every planet has his own moons, but only if they're full
moons, no matter their size, they are able to emit a Brute wave more powerful
than 17 million zenos".
Then he starts creating a powerball within his hand,
and more tells "... some Saiyans are able to make a little artificial
moon more powerful than 17 million zenos! This is possible by mixing the
oxygen existent on the planet with this powerball!" No sooner said
than done, he throws the sphere of energy in his hand and, when it reaches
a suitable height, he makes it to explode.
Then Vegeta looks at the artificial moon he made and his transformation
And here are some important details about this transformation.
Saiya-jin children aren't yet able to have self-control (when they turn
Ohzaru), so they act following their own destructive instinct and, when
they return normal, don't remember anything. For this reason, they're
subjected to a special training in order to control their own transformation
and, in this way, they manage to have self-control and full awareness
and are also able to talk. The Saiyans, by turning Ohzaru, become 10 times
as powerful as before.