How did Richard pryor catch on fire?

He was freebasing cocaine and drinking 151 rum. Allegedly, his daughter said that he poured the rum on himself and lit it. He then went running down the street on fire.

Fire is already on fire, thus fire cannot catch fire: it already is on fire.

Catch fire is a fictional term used in anime, and anime movies. Catch Fire means to catch fire, for example, you would catch a ball. Catching ON fire is lighting yourself on fire, or something else...

almost anything some metals cant catch on fire...