TARDIS cradle

The Cradles were technology created by the Time Lords of Gallifrey.

A Cradle facility was established by the Gallifreyans of the future to produce War TARDIS's. They were dimensioal transcendental locations which were used to birth these deformed TARDIS variants for the against The Enemy.

When Compassion entered the Cradle, she communicated with them and they expressed rage at what had occured to them. This rampage caused the dimensions within the Cradles to fluctuate. (BBC: The Taking of Planet 5)