Biden was ridiculing Trump for spitballing and talking out of his ass at a press conference where he made himself look like an imbecile. Then it became a national joke. This is what Trump actually said, which is still unbelievable when you consider this is the president of one of the most powerful countries in the world talking :
"A question that probably some of you are thinking of if you’re totally into that world, which I find to be very interesting. So, supposedly we hit the body with a tremendous, whether it’s ultraviolet or just very powerful light, and I think you said that hasn’t been checked, but you’re going to test it. And then I said supposing you brought the light inside the body, which you can do either through the skin or in some other way. And I think you said you’re going to test that, too. Sounds interesting, right?"
"And then I see the disinfectant, where it knocks it out in one minute. And is there a way we can do something like that, by injection inside or almost a cleaning, because you see it gets in the lungs and it does a tremendous number on the lungs, so it’d be interesting to check that, so that you’re going to have to use medical doctors with, but it sounds interesting to me. So, we’ll see, but the whole concept of the light, the way it kills it in one minute. That’s pretty powerful."