UV light
At the White House press conference on Thursday, the president said, “Suppose that we hit the body with a tremendous, whether it’s ultraviolet or just very powerful light. Supposing you brought the light inside the body, which you can do either through the skin or in some.”
The scientific criticisms and humorous takes that followed the press conference was automatic. The president of the United States was theorizing a method that would almost surely give people cancer.