Unknown scratch

Aron and friend went to college for MQA interview section this afternoon, around 12.

As usual, need to "mok"(camp) for parking. They saw there is 1 near the cafeteria, Aron try to park in, but that is very difficult, as the drawing below:
Green = legal parking
Red = Illegal parking
Black = Me

So Aron reverse and then he saw a parking in front and straight away go in. Settled.

After college, Aron and his friend went to Dataran Sunway for a drink, then he smell that something like melted plastic in the car. So he went to mechanic Lim. He noticed that there is scratch near my bumper, at the left.

Is it when Aron trying to park in the difficult parking?
Or hit something made of brick? coz when he touch the scratch, he found something like powder on it.....