Protoforms 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.
When a Protoform lands on an populated planet, such as Earth, it quickly disguises itself and gets a vehicle mode, stealth force and alternative mode (these Protoforms are called Protoform Entry. They are technically unarmored Protoforms that didn't taken an Alternate Mode yet ).However, the Decepticon protoforms in Dark of the Moon did not change into new forms, as they were fighting a battle (See picture above) except a Sideways - like Decepticon transformed himself into an Audi, a Barricade - like Decepticon transformed himself into a police car and a Long Haul - like Decepticon who turned himself into a garbage truck, a second Long Haul, Scrapper, Bonecrusher and Brawl looklikes Decepticons and two others decepticons who takes the form of firefighters trucks.Autobot protoforms look more humanoid while Decepticon protoforms look more monstrous and demonic.