Thinking about TFA Sari's origin and how 'fetal' her origin protoform looks. So protomatter headcanon time!
It's established that protomatter is mined from the quarries in the sonic canyons. Then the protoforms are contructed and used for molds, but what about the processes in between?
So I'm thinking that the ore is transported to factories as plain rock. The factories take the sonic canyon rock, refine it into a near pure form of protomatter ore, place the refined ore chunks into pods, then seal it all up.
The pods are then transported to the Cyber-Ninja dojo and locked in the vault where they are "nurtured in the light of the Matrix Chamber" to be used at a later time.
With this, the Matrix Chamber is a conduit of Vector Sigma that slowly develops the protoform pods as they rest in the vault. Basically, growing protoforms.
The ore in the pod goes from a rock of indistinct shape, softens into putty, then begins to form limbs and body features. Going from infant development all the way to a matured protoform that can then be used in a mold.
So when Lockdown steals the cache of protoforms, he takes both mature and immature protoform pods indiscriminantly. The mature ones can be used to make more Cybertronians while the immature can only resupply lost protoform from grievous wounds.
With that in mind, Megatron kept a cache of an immature-type protoform in his subspace to use in the event he is mortally wounded to quickly replenish protomatter and continue the battle. But, after his descent into Earth's atmosphere, he is knocked offline and too damaged to reach the pod so it sits there, dormant.
In Sumdac's lab, the immature pod is ejected from Megatron's subspace and found on the ground for Sumdac to accidentally imprint and instantly sculpt into a technorganic.
I guess this is also technically my thoughts on Sari's origin? Her beginnings are just total coincidence and a series of happenings that led to her creation. Almost like how evolution of organic life is just a series of coincidences all the time.
