The Shadowzone is an alternate dimension outside the main reality. Its existence means that anyone trapped within it is unable to interact with normal space as they are out of phase and seemingly encased in a limited amount of space.
During a battle against Starscream, the activation of two simultaneous GroundBridges led to the portals feeding off each other at the same moment. Thus, Miko Nakadai, Jack Darby, Raf Esquivel, the Terrorcon Skyquake, and Starscream's severed arm got caught in the resulting explosion which catapulted all of them into a Shadowzone. Whilst Optimus Prime and the Autobots searched for their human friends, Jack managed to alert them of being trapped in an alternate dimension by sending a text to Miko's phone, which was left at the Autobot base. This allowed Ratchet to open a portal with the GroundBridge to allow the three humans to escape the Shadowzone, along with Skyquake's hand which had been chasing them. This left the trapped and undead Skyquake the remaining occupant of the Shadowzone.
Starscream later mentioned that Skyquake was likely still trapped in the Shadowzone while under a cortical psychic patch interrogation session, much to Dreadwing's shock.
After Soundwave GroundBridged the Wreckers off the bridge of the Nemesis, Jack and Miko, the latter in the Apex Armor, boarded the ship. Soundwave attempted a repeat performance, giving Raf the opportunity to open a second GroundBridge, recreating the original accident and trapping the unwitting Decepticon in the Shadowzone.
After involving a bridge accident, Soundwave came out of the portals, and then later pushed Bumblebee into the Shadowzone. Bumblebee was surprised when he tried to push Soundwave, he went right through him. Bumblebee later thought what Jack, Miko, and Raf did when they were trapped in the Shadowzone. He remembered and told Denny, Russell, and Fixit to trick Soundwave into the Shadowzone, and it worked. He later remarked how their plan would probably work four percent.
Soundwave once again freed from the Shadowzone with the help of Cyclonus for their common goal to summon back Megatron. After Soundwave and Laserbeak defeated by the Autobots, Hi-Test decided to stay in the Shadowzone as his new home.
- Jackson Darby (formerly)
- Miko Nakadai (formerly)
- Rafael Esquivel (formerly)
- Skyquake (currently, presumably destroyed)
- Soundwave (formerly)
- Laserbeak (formerly)
- Bumblebee (formerly)
- Hi-Test (currently)
- Raf specualtes the reason no one can hear what goes on in the Shadowzone and why the occupants can walk through others is because they are moving at hyper-speed.
- As shown by Miko if someone is heavy enough, they can resist being pulled into the Shadowzone.
- Terrorcon Skyquake was presumably destroyed when Unicron was trapped in the Allspark's container by Optimus Prime in Predacons Rising.