Time-jump mechanisms are a method for traveling backwards through space and time. The portals can be stationary, summoned by a bank of computers onto a specific point, or triggered by an individual carrying a hand-held remote control device.
Travel back in time requires a mass substitution, which acts to preserve the constant state of matter and energy in the universe. Therefore, when someone travels backwards in time, a being of equal or similar mass is displaced into an other-dimensional Limbo until the traveler returns to their own time. This displacement effect is explosive to witness, and more than once observers have presumed the displaced individual was atomized on the spot.
Marvel UK Comics continuity
A time-jump mechanism was first used by the newly-upgraded Decepticon leader known as Galvatron, who had been rescued from death by Unicron and reformatted into a more powerful form. Wanting to maintain his extra power while still breaking his master's leash, Galvatron travelled back in time from 2006 to 1986 with his lieutenants, Scourge and Cyclonus. His plan was to build a massive space cannon and bury it unnoticed underneath the spot where the Autobots would one day construct Autobot City. Then, he would set a timer so that the device would go off in 20 years, blasting up through the Autobot City and striking Unicron at a pre-determined location, destroying the Planet-Eater and his hated foes all in one felt swoop.
To accomplish his mission, Galvatron temporarily displaced Optimus Prime, Prowl and Ratchet, then disabled his younger self Megatron, and commissioned the Constructicons to create his masterpiece weapon. His plans were disrupted, however, due to three time-travelers from his own era. Unicron was aware of Galvatron's treachery, and subtly influenced the minds of three Autobots (Hot Rod, Kup and Blurr), sending them to use Galvatron's trans-time dimensional portal to jump back in time after him. The Autobots were successful in diverting Galvatron by orchestrating a complicated series of events that convinced him he had traveled sideways through time as well as backwards, landing in a past not his own. Convinced that any alteration to this past would be fruitless for his present, Galvatron returned to 2006 with his men. The Autobots soon followed.
Later, after being defeated by the arisen Rodimus Prime in battle, Galvatron escaped by using his time-jump trigger device to return to 1986. His presence in the past was a constant thorn in the paw of all 20th century Transformers, as well as the future Autobots and Rodimus Prime. A bounty hunter named Death's Head pursued Galvatron back in time to collect the reward on his head placed by Rodimus. Rodimus hadn't realized Galvatron had time-jumped, however, and upon hearing both the Decepticon and the hunter were loose in the past, he commissioned a jump back to 1986 himself along with several Autobots. His comrade Wreck-Gar attempted to jerry-rig Galvatron's remote to reverse the time-jump and send them all back to 2006, but it ultimately failed: Galvatron had somehow taken himself out of the temporal effect of the remote, and so only the Autobots and Death's Head returned to the 21st century. Galvatron had to be defeated (albeit temporarily) by a pair of 20th century Autobots.
The time-jumps became a serious problem in the aftermath of a 2008 battle with Unicron on the planet of Junk. During an explosion, Death's Head was hurled through a time portal with Scourge and Cyclonus. While Death's Head ended up falling sideways through time into another universe, the two Decepticons wound up on Cybertron 20 years in the past, but WITHOUT having triggered the requisite mass substitution effect as per usual time-jumping. This anomaly caused a time storm to begin slowly building at both ends of the timestream, and it eventually grew so large as to utterly consume the planet Quintessa in 2008.
Simultaneously in 1989 and 2009, the time storm began to seriously threaten the stability of the universe, with apocalyptic weather and natural disasters plaguing Earth at both ends of the timeline. Things had gotten very bad very quickly once Megatron had killed Cyclonus in the past, thus dramatically increasing the odds that he would never return to the future and restore the balance to the timestream. A massive battle arose, with various factions of Autobots and Decepticons from both time periods attempting to end the threat Galvatron's prolonged presence in the past was having. In the end, Optimus Prime and Shockwave managed to toss Scourge and the deactivated pieces of Cyclonus into the time storm, while the storm itself consumed Galvatron after he refused to simply lay down and die, regardless of the injuries he sustained. Galvatron was ultimately ripped apart by the storm, and consumed utterly so that the timeline could reboot and restore itself to a proper order.
With the threat abated, Optimus Prime said good-bye to Rodimus Prime and his soldiers, and passed on a bit of wisdom: Destroy your time machines. ALL of them.
- Galvatron, Scourge and Cyclonus => Optimus Prime, Prowl, Ratchet
- Hot Rod, Kup and Blurr => Shockwave, Thundercracker, Frenzy
- Galvatron => Skids
- Death's Head => First Aid
- Rodimus Prime, Kup, Blurr and Wreck-Gar => Unknown
- Scourge and Cyclonus => No mass-displacement, initiates time storm