Casey Affleck is currently shooting a documentary about Joaquin Phoenix and his transition to hip hop artists. It has been suggested that most/all of this is part of a very Andy Kaufman-esque joke.
Or, he could just be completely zonked out of his mind.
... now as for Cripsin Glover (dad from Back to the Future), I don't know.
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If you want to see something else more disturbing search ''clowny clown" in Youtube. I'm not going to link it because it was too disturbing. Glover was 100% serious and it was not made for comedic value. Watching that one first might make this one make more sense (to see how crazy the guy was).