What would be the result of putting kerosene in your car gas tank?

A little while ago I stopped at a convenience store for my newspapers. (Yeah, dino). There was an elderly lady at the gas pumps, but she was trying to use the kerosene pump. Yeah, scary that she’s even driving. I stopped her and explained she needed the gas pump and after she kept working on getting the kerosene pump into her car, I took it away from her and put the gas pump in for her. I assume she made out okay, because I left fast wondering about the upcoming explosion. But I have been wondering, how big of a mess kerosene would make of a gas powered car? As always, humor is appreciated.