John Oliver had some choice words for America following the United Kingdom's vote to leave the European Union, urging voters to pay very close attention to the fallout. The vote, which has since inspired a petition demanding a do-over that keeps crashing the government's website, was soundly supported by presumptive GOP nominee Donald Trump. As Oliver warned on Sunday's Last Week Tonight, that's a hell of a red flag.

"The UK this week voted to leave the European Union, a decision that has shaken the world," Oliver told his audience. "And not in a 'Muhammad Ali beating Sonny Liston' kind of way. More in a 'Those IKEA meatballs you love contain horse' kind of way." Though Prime Minister David Cameron's subsequent decision to step down brought Oliver joy, the former Daily Show contributor said his exit was profoundly bittersweet.

"It's like catching an ice cream cone out of the air because a child was hit by a car," Oliver said. "I'll eat it, but it's tainted somehow."

Ice cream puns aside, the global stakes in the wake of the baffling Brexit vote are impossible to overstate. "Britain was already independent," Oliver noted before taking aim at the noticeable Independence Day vibes of Brexit supporters. "In fact, it's what many other countries celebrate their independence from. And second, the sequel to the movie they're quoting actually opened this week and features the wholesale destruction of London, which is beginning to feel pretty fucking appropriate now."

Though it's easy here in the States to brush off the Brexit fallout, Oliver insists that's a terrible idea for one very specific reason: Trump. "You might think, 'Well, that is not going to happen to us in America. We're not going to listen to some ridiculously haired buffoon peddling lies and nativism in the hopes of riding a protest vote into power,'" Oliver said. "Well, let Britain tell you, it can happen. And when it does, there are no fucking do-overs."