Mass substitution

Yet more black repaints

Mass substitution is an integral process in making a time jump in the Marvel UK comics. In order to maintain the mass balance of the universe a time traveller must displace an equal mass from the time zone they are entering. Those displaced are taken out of normal space and deposited in limbo. They remain there until the time traveller who displaced them leaves their time zone.

From Teletraan I: The Transformers Wiki, a Wikia wiki.