When someone undeservingly stumbles upon
success, through sheer
luck and usually minimal skill of their own, similar to that of the cartoon character Scooby
Doo who would often catch the villain by literally stumbling upon them, usually after he had fallen over or been involved in some sort of zany accident.
Person 1: Hey, how'd you go in that exam?
Person 2: Dude I got
like 95%
Person 1: How? I got
like 65% and you told me you didn't even study
Person 2: It's the Scooby Doo Effect
man.