Hibernation unit

The Hibernation unit was an item of Silurian technology which allowed them to enter into a state of hibernation in order to survive harsh conditions and the centuries. They resembled coffin shaped blocks where a Silurian resided within them.

The Silurians built the hibernation units during their rule of the planet when they first detected a planetoid that would devastate the world and leave it uninhabitable. It was decided that the race would enter into hibernation until the planet became livable once more. However, the mechanism was faulty and did not reawaken the race until a new power source was discovered which was when humanity inherited the planet. (DW: Doctor Who and the Silurians)

The criminal Tulok, after being exiled by his people for genetic crimes, wreaked his revenge on his race by sabotaging the hibernation chambers which destroyed several settlements except for a dozen or so. They made use of hydrogen fusion reactors as a power source. (BFA: Bloodtide)