Some members of Freeza's race have been shown to possess the ability to transform into several forms, each holding different power and speed capabilities. Over time, Freeza's power became so great that his body could not comfortably contain it, and a series of physical transformations were developed to limit his actual strength. While other beings in Dragon Ball Z transform to increase their power, Freeza transforms to control and contain it. His true form is his fourth form, with each of his other transformations meant to restrict his power and conceal it from his enemies. Freeza even says upon transforming to his second state that he has a harder time controlling himself and his power due to the immensity of his current strength. That would suggest that the second and third forms are mere physical augmentations which would allow Freeza to build enough strength to revert to his true form. While changing shape from his "first-form", each alteration builds on the previous.
In all, Freeza demonstrated four transformed states, each with increasing power (some larger than others and each resulting in different physical attributes). Freeza may also use these transformations to purposely decrease his power in order to torment his opponents by giving them a false sense of hope. They are all capable of surviving even the most horrific injury and are able to survive even in the vacuum of space.
Coola as an extra transformation learned to go beyond his brother's. Originally, Coola merely told Goku that he had one more transformation than Freeza.
FREEZA
COOLA: SUPER EVOLUTION
The fifth and most powerful form is only seen being used by Coola, in which refers to this state as "Super Evolution" who uses this form against Goku, and nearly destroy the planet. He increases dramatically in size, speed, and strength; four horns grow to form a crown atop his head as spikes form on his forearms, and he now sports a face-mask of sorts, hiding all facial features except his eyes, which are now red without pupils. It is notable that he possesses an extra transformation. Although Freeza used his transformations to suppress his power, Coola utilizes a way to actually enhance his power through transformation, developing a powerful, extra form. However, this form was still no match for the power of a Super Saiyan. It was then that Coola realized that Goku was the Saiyan child he had allowed to escape nearly three decades ago, and that in scolding his brother and not lifting a finger he had been far too soft himself. After this, Coola incinerates in the fires of the sun.
Another form is A state achieved by Freeza in Revival of "F", that is referred to as "Golden Freeza", which is also known as "Ultimate Evolution". Freeza attained this form during the time he spent four months training for his invasion of Planet Earth and revenge against the Saiyans.
In this state, Freeza's skin turns dark lilac on his face, hands and feet and he gains golden armor that covers most of his armor which consist of dark gold in his arms and legs, lighter gold in his torso, tail and head. It is also missing his purple plates on his shoulder. His aura changes, becoming fiery similar to that of a Super Saiyan God.
FREEZAPhysically ruined while caught in Planet Namek's explosion after his defeat, what remained of the still-living Freeza was salvaged and rebuilt with cybernetic enhancements by scientists under the order of King Cold. The whole of the lower half of his body and right side of his face was replaced with scarring and metal accouterments covering what little was left of his organic self. These enhancements allowed him to exceed the limits imposed by his fully organic form, though by how much or in what ways is unknown. In the original manga, Gohan mentioned that he was nowhere near the power he displayed against Goku, but Vegeta said he was much stronger than before. In the PS2 game Super Dragon Ball Z, a new design for Mecha Freeza was created by Akira Toriyama which had a rocket launcher mounted on his shoulder. In the Remastered Box sets, this form has a slight mechanical sound to his voice. Freeza goes to Earth with King Cold to get revenge on Goku and to destroy the Saiyans, but Trunks, a boy from the future, stands in their way. It can be guessed that in this form, Freeza's special moves and fighting style are about the same as when he was in his final form. Thinking him dead, both father and son are stunned when Mirai Trunks fires a Burning Attack out of nowhere. Fuming, Freeza becomes oblivious to his opponent's position, and is surprised and sliced in half by the Saiyan youth before being cut to pieces and vaporized in an effortless blast for good.
After his death, Mecha Freeza was trapped in an coccon in Hell guarded by the Angels of Hell. Upon revival by Sorbet and Tagoma, his remains (after being sliced by Mirai Trunks) were placed in a regeneration vat, reverting back to his first form.
COOLA
After blasted into the sun, Coola's remains float around in space and eventually fuse with the Big Gete Star, a giant machine planet. The Big Gete Star revives Coola by finally fusing with his brain, eventually allowing Coola to take control. Coola set a course for New Namek, intent on draining the planet and using the Namekians as fuel for the star. Dende, learning of this horrible news, calls to Earth's warriors for help; The Z-Senshi then travelled to New Namek, ready to assist it's people. Upon arriving, they find many robotic beings known later as Cyclopian Guards, as well as the revived Meta-Coola, now in a wholly metallic and enhanced body. Stronger than ever, he is able to easily repel Goku even as a Super Saiyan, and had it not been for the unlikely appearance of Vegeta, Goku most likely would have been killed. However, even the two Super Saiyans run into difficulty handling Meta-Coola; the nano-machines that made up his body would instantly detect and repair any defect, and make it so that defect would no longer hinder the "new-and-improved" version. Only by working together in a joint attack would Meta-Coola finally be destroyed. Vegeta shows up and joins the battle, and they soon dispose of Coola. However, the Big Gete Star housed an army of Coola clones. Outnumbered and drained of energy, Goku and Vegeta are captured and transported to the Big Gete Star's core to be used as energy to power it to create an army of Metal Super Saiyans. As Coola is leeching their Super Saiyan strength via strange wires, Goku and Vegeta regain consciousness and release all their Super Saiyan energy to the wires, overloading the system. They then blast the true Coola with the last of their energy, causing his ultimate demise as the Big Gete Star explodes in New Namek's orbit.