Protoforms (プロトフォーム, Purotofōmu) consist of an unspecified, free-flowing, metallic matter layered over basic robotic systems. In many universes, a protoform is the first stage in a Transformer's life cycle. These protoforms only await a life-giving spark and the alt-form information necessary to transform them into fully functional, living Transformer beings. Often, protoform modes are used to transport Transformers on intergalactic journeys.
Protoforms are transported or stored in stasis lock, in which state they look like smooth, robotic humanoids. When not in stasis lock, protoforms are a roiling mass of liquid metal around their internal frame.
Existing Transformers can place their sparks in a newly created protoform in order to assume a new form, or to recreate their old one. This is one way of rapidly repairing even the most extreme damage, by virtue of totally replacing the body.
Protoforms are created from "proto-matter", mined from Cybertron's Sonic Canyons, during the closing stages of the Great War. In their pre-life state, they resemble featureless grey mannequins, and are stored in pods that line the walls of the secret Matrix Chamber hidden in the dojo of their assigned protectors, the venerable Autobot Cyber-Ninja Corps. Customarily, prior to being brought on line, protoforms are placed into "moulds", pre-built robot shells, which their proto-matter expands to fill. Following this, either the AllSpark or Vector Sigma is used to bestow them with a spark. It is possible, however, to forego the use of a mould and place a spark in a protoform directly. The same basic mould can be used for multiple protoforms, leading to similarities in body-type and transformation schemes; the 65356-9292-346 type is particularly popular and widely-used. Where humans would describe themselves as being "born", Transformers are "protoformed". Additionally, "protoform" is sometimes used pejoratively in Cybertronian society as a mocking name for the young or inexperienced.
Cyber-Ninja sensei Yoketron revealed the Matrix Chamber and its legion of protoforms to his student Prowl, lamenting that while they should be Cybertron's next great generation, they would wind up being used as an army of last resort if Project Omega failed to bring the war to an end. Subsequently, while Prowl was absent on a quest to commune with the AllSpark, Lockdown, another former student of Yoketron's, attacked the dojo and stole nearly all of the protoforms for Megatron. As luck would have it, Project Omega did succeed in ending the war, and when the Decepticons were exiled from the planet, they secretly took the stolen protoforms with them. However, without the AllSpark (which was already been launched into space by the Autobots during the Great War to keep it out of the Decepticons clutches), Megatron had no means of bringing the protoforms to life, and so they remained in storage aboard the space cruiser versioned spaceship the Nemesis for years.
Some time in the future century, a protoform which had been granted a spark through means unknown, in a highly atypical foetus-like form, somehow materialized on Earth, in the laboratory of human scientist Isaac Sumdac. When Sumdac touched the protoform, it scanned his DNA, and reconfigured itself into a techno-organic form resembling a human baby. Sumdac "adopted" the strange little creature, naming it Sari, and raising her as his daughter, never telling her of her true origins.
Eight years after Sumdac found Sari, the quest for the AllSpark brought the Transformers' war to Earth, and Sari and her father became allies of Optimus Prime's Autobots. To forge a power base for himself, treacherous Decepticon lieutenant Starscream set up base in the Nemesis (which he had crashed on Earth's moon), using the protoforms that still remained in its hold to create an army of Seekers in the form of clones of himself. Starscream himself had previously died, but was being sustained through a sliver of the AllSpark wedged in his forehead, and so by breaking off tiny chips of it, he was able to give his created Seekers—Skywarp, Slipstream, Sunstorm, Thundercracker, and Ramjet—the spark of life.
Later, Megatron followed Starscream's example, using three protoforms and three AllSpark fragments to create giant cross-breed clones of Lugnut and Omega Supreme, the Lugnut Supremes. While Megatron readied his new war machines, Starscream—who had by this point spent a protracted period of time as a decapitated head—used a protoform to create a new body for himself, but it didn't last long: to prevent Starscream from betraying him again, Megatron destroyed his new body, and all the remaining protoforms, save three. These three protoforms were then recovered by Optimus Prime's Autobots during their battle with the Lugnut Supremes. Sari believed that she was originally one of the protoforms who had been aboard the Nemesis, but her unusual shape and form while in protoform state, and the unanswered question of how she wound up in her father's lab, left the matter lacking in a definitive resolution.