That creepy pasta is old. A fairly good one though.
Someone on another board pointed me to that site after posting this, too. This particular one was damn well written.
However, that steered the conversation towards other stuff. The following REALLY did happen:
This is a bit disturbing to see, and real. So be warned before you click on the link.
A Soviet scientist in the 1950s, the same scientist that made heart and lung transplants possible today, experimented with head transplants.
He successfully attached one dog's head and front legs onto a German Sheppard. And the operation was successful, however both dogs died 4 days later from immune-system complications. There's even footage out there on YouTube you can see of these dogs, with scientists feeding both heads and all.
Crazy stuff out there.
http://motherboard.vice.com/blog/soviet-scientists-made-this-two-headed-dog