1. Sergei Brukhonenko
Also known as the dog decapitator, Bryukhonenko performed crazy experiments on dogs which led to the development of open heart procedures.
He developed a primitive machine called the autojektor which he used to keep the heads of severed dogs alive. To show his achievements, he displayed one of the heads to an audience in 1928.
He banged a hammer on the table to prove that it was alive and the head actually flinched. He then shone a light on its eye and the eye blinked.
He also fed it a piece of cheese and the remnants popped out of the esophageal tube leaving the viewers extremely disgusted.