The actress was inspecting her new car when the vehicle appeared from nowhere and started careering towards her.
The CHARMED star had just purchased her automobile and driven it off the dealer's lot and taken it to her best friend's house to have her husband take a look and explain some of the features.
While the group was admiring her new purchase, an SUV came barrelling down the street towards her.
McGowan recalls, "It smashed my car in half and threw it forward into oncoming traffic."
The reckless driver stopped to inspect the damage, but seemed unrepentant about nearly killing the actress.
She adds, "I'm totally shocked, and the guy gets out of the car, and this is how my brain works - he's wearing this black turtleneck and I've never seen so much dandruff in my life.
"He just stood there, smoking, and I said 'Are you sorry?' and he said (unconvincingly) 'Yes, I am sorry. It was my fault.'
"I'm thinking, 'You almost killed me and you have horrible dandruff. There might be more of an apology that should be coming!'"