Jonathan Weems's ray machine

The "ray machine" was a bulky device invented by the American scientist Jonathan Weems, created by refining the energies produced by redwood tree sap.

If placed under its ray for 24 hours, a human would find their metabolism slowed to match a redwood tree's, making them functionally immortal at the cost of paralysing them. Weems's discovery was misrepresented in sensationalist press releases, driving Luther Kane, a ruthless businessman who desired immortality, to covet the machine. After Weems refused to sell it, trying in vain to convince Kane that he wouldn't like the results, Kane stole it from Weems and took it back to his home, where he installed it in his cellar, locked himself in, and switched it on. By the time he realised he was losing the ability to move, it was too late for Kane to use the antidote ray machine that Weems had also insisted on giving him. (COMIC: Dr. Who's Time Tales)