Infraspace

Infraspace is a region in the IDW comics portion of the Generation 1 continuity family.

Not much is known of infraspace. A Transformer can seemingly exist there without a body, or perhaps it is where a Transformers' mind or spark exist when their bodies have been destroyed.

Fiction

IDW comics 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 issue 6

The connection between infraspace and the Dead Universe, if any, has yet to be revealed.