Kaznak Simu-Systems were extra-terrestrial machines that could transform the dreams of sleeping minds into solid objects.
In 2016, Professor Nakatomi bought a Simu-System off of the black market to create a 3D video game system. He tested the system with two boys who were fans of a kaiju action figure series. When the boys fell asleep in the Simu-System, they dreamt of their their two favourite monsters fighting each other. The Simu-System created the monsters in the streets of a japanese city and caused widespread damage. UNIT cleared the area and tried to shoot down the monsters. The Twelfth Doctor tracked the monsters to the source and found the Simu-System. He used his sonic screwdriver to hack his mind into the Simu-System's data core and switch it off. (COMIC: Big in Japan)