Six students were fined almost £5,000 after police broke up a house party flouting coronavirus restrictions.
Caught on bodycam footage scores of guests were filmed hiding in upstairs bedrooms at their Bristol digs as music blared out.
They were said to be celebrating a friend's 20th birthday at the house and told officers they were "just chilling".
In the body-cam footage, one officer said: "So we're going to start looking in all the bedrooms.
"If one of you wants to be the adult and go and get everyone out? Because I [think] you're hiding, and that's why you were taking your time today to answer the door.
"So if you want to be adults, you'll be treated like adults. Okay? So if there's everyone else here, if they come down now, we'll deal with everyone now.
"It might be that we give you a warning, but if everyone is going to hide in the bedroom and play silly b * s then we'll give everyone a £200 fine."
A terrified student quickly pipes up in response "I'll be the adult" and three of the hosts awkwardly shuffle out of the room.
The camera then cuts to one of the cops dramatically opening the door, to reveal dozens of drunk undergrads crammed onto the couch in the student home.
The Avon and Somerset Police officer, furious, blasts: "Okay. Blimey, I didn't expect quite [such] a big audience.
"We're all aware of the coronavirus regulations. Do we know what they mean? Where can we meet if we're meeting together?"
To which the sheepish students reply: "Outside."
He questions: "How many households? This is totally unacceptable and flies in the face of everything we've been doing as a nation for the past year."
In a statement, inspector Ruth Gawler said: "The vast majority of people have played their part by adhering to the lockdown rules at the start of the year.
"And we're thankful they are continuing to comply with the restrictions and advice currently in place.
"However, there is a small minority of people who are selfishly choosing to break the rules that are designed to help save lives.
"Our approach to dealing with such incidents remains the same - we will engage with the public, explain the rules and encourage them to comply.
"But enforcement through fines remains an option, especially for those responsible for the blatant and deliberate breaches we've been called out to deal with in recent days.
"We fully understand everyone is delighted by the easing of restrictions, but we continue to urge people to be cautious and follow the rules to limit the spread of COVID, which has already claimed thousands of lives across the country."
The force also revealed they had broken up another student house party that night in the city, as well as a lock-in at The Waggon, in Taunton.
