A stasis chamber or suspended animation chamber was a machine designed to suspend the biological functions of its occupant, keeping them alive and unchanged for prolonged periods.
The Tulk used a type of stasis chamber that contained a bubble of damped space-time. They stored weapons in one for safekeeping. Norma Brunner heard a conversation about it, and thought they were talking about someone named 'Stacy Chambers'. The Seventh Doctor stopped the Tulk and the Annarene from opening it and using the contents to start a war. (PROSE: Relative Dementias)
The Fisher King planned to place himself inside a suspended animation chamber to await the arrival of his people, while the ghosts he created broadcast his coordinates. The Twelfth Doctor tricked him into leaving the chamber behind, and then used the chamber himself to return to the future. (TV: Before the Flood) The chamber was later discovered by the crew of the Drum. (TV: Under the Lake)