That can't be definitely proven. I propose an theory: Schrödinger's DannyAlcatraz! If you place an black metalhead* in a party, against environmentally induced quantum decoherence, that black Metalhead will be either DannyAlcatraz, or not, or both simultaneously. However, if you ask him his name, his response will be either "yes,", "no," "Why do you ask," or a punch in the face.
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*As implied by this thread, it is assumed that black metalheads are exceedingly rare. Therefore, there is a high quantum probability that any black metalhead will be DannyAlcatraz especially if they also practice law, play dnd, or are highly educated.