That's a reference to Josef Mengele, also known as DR. GREEN. "Nicknamed the "Angel of Death" (German: Todesengel),[1] he performed deadly experiments on prisoners at the Auschwitz II (Birkenau) concentration camp, where he was a member of the team of doctors who selected victims to be murdered in the gas chambers,[a] and was one of the doctors who administered the gas." Look it up!
