School Oil Spill

I don't know if I ever talked about a particular prank played in my school, but I was thinking about it today as I walked to class with my friend and we talked a bit about it.
A few months ago, some of the older kids were up to jokes and pranks. Most did funny jokes that didn't hurt anyone, such as using noise makers in the corridors. However one joke/prank really stood out from the rest.
I was in a class that was nearby a main, busy corridor. There is a ramp going down on one side of the corridor. While everyone else was busy in class doing school work (as they should be), someone poured olive oil all over this corridor.
When class let out, kids streaming from everywhere came to this corridor. Dozens walked into this terrible mess. Every child who walked into the oil had to call home or ask a friend for a pair of shoes because simply walking wouldn't be safe. However this was not the end. Very many kids, especially those on the ramp, slipt and fell. One girl my age slipped and fell, splitting open her head. Another girl required stitches, and a boy my age hurt his wrist. There were other, more minor injuries. Many kids had oil on their clothes, which is a hazard. If a young, healthy girl got hurt badly I can only imagine what would have happened if it were an older or elderly teacher or a child with an injury or disability.
Kids and teachers were very good at handling the situation. They helped direct others to different routes and got those hurt and those who were slippering back to safety.
I think whoever did this prank was either really stupid to think it would just be harmless fun or had a lot of hatered against the other students and teachers.