A prank is a practical joke on someone. I would watch "Prank Patrol" for some examples. Anyways, a simple prank is telling someone they're late for work/school, and messing with all of their clocks....
It could well be an unrelated Third Party- such as a Priest or a sporting coach- too many scandals of this type have happened! ( numerousw clerical cases and the recent Paterno-Sandusky affair.) a...