Infraspace

Infraspace is an interdimensional region from the Generation 1 continuity family.

Not much is known of infraspace. In theory, it is the transitional infraspace between life and death. It is also known as limbo and has been described as "virtual nothingness". Under certain circumstances, a Transformer's consciousness can apparently exist there without a body.

Fiction

Dreamwave Generation One comics

According to Perceptor, Optimus Prime and Megatron passing through a space bridge together caused an "imprint" of the event to appear and follow them through a parallel course in infraspace. He expected that a new portal would appear once the imprint caught up with their destination. The Age of Wrath Pt.3

IDW Generation 1 continuity

Optimus Prime had received a severe beat-down from an Ore-13-powered Megatron, and was on the verge of terminal shutdown. In a desperate ploy, he transferred his higher functions into his trailer section, giving the appearance of lifelessness.

During the transfer, Prime's consciousness drifted through infraspace. While there, he felt a sinister presence that seemed to recognize and watch him. Escalation #6 That presence was later revealed to be Nova Prime Spotlight: Optimus Prime who was, at the time, an undead inhabitant of the Dead Universe and had changed his name to Nemesis Prime. Devastation #3 However, the exact connection between infraspace and the Dead Universe is unclear.