Students at Cumberland Valley High School, outside of Harrisburg, say yesterday's food fight was a planned senior prank.
One student who was in the cafeteria, told reporters that a student stood up and threw his tray of lasagna at lunchtime yesterday.
Then there was a long pause, before other students started doing the same thing.
The principal has apparently told students that some of those caught in the act will not be allowed to go to the senior prom.
Others will not be allowed to walk at their graduation.
And a number of senior athletes will not be able to compete in any more events.
