The Beast has given it a name. Parabiosis

The grim, somewhat vampiric, practice of swapping blood between a young person and an older person is called parabiosis.

Scientists discovered in the 1970s that fusing the circulatory systems of animals together — sometimes for weeks on end — had surprising results.

The younger animal would age prematurely, whereas the older animal was rejuvenated.

But a stark warning was issued by the FDA, who said it feared some Americans were receiving rogue blood transfusions.

https://www.dailystar.co.uk/news/latest-news/777878/immortality-biohacking-secrets-dangerous