A post-GCSE exam party got out of hand when around 2,000 drunken teenagers stormed a beach and created havoc.
Officers seized cannabis, laughing gas, and a knife from students from a beach in Chalkwell, Essex on Friday June 14.
Glasses were even thrown at police and there were also reports of youngsters having their drinks spiked.
Some of the teens were so drunk or high they needed taking to a hospital, with many claiming their parents had bought the booze for them.
Southend Police said 16-year-olds from five separate schools met up that night to celebrate finishing their exams.
The event needed more than two dozen police officers to break it up and send the schoolkids home.
Southend Police wrote on Facebook that there were around 1,500 to 2,000 kids near the beach in Chalkwell and around 100 to 150 in Thorpe Bay.
The statement continued: Whilst its clearly an exciting time for the kids finishing school exams and taking their next step in life, its not really acceptable to go and get smashed on the beach.
Its not acceptable to throw bottles at Police Officers and PCSOs, its not acceptable to cause disruption to other people, and its not acceptable to spike other peoples drinks.
We confiscated a lot of alcohol from the kids, many of those kids when told it was going asked us if their parents could come and collect it as they bought it for them.
The force added it would like to remind parents that its an offence to buy alcohol for someone under the age of 18.