What is Donald Trump? Not who is he—we know quite enough about that—but what is he, taxonomically? Is he primarily politics or entertainment? Is he a distraction, or a demagogue-in-the-making? Will his views—enormous walls, mass deportations—be given the power, in short order, to affect the lives of real people, in the real world?

Many in the media, at least, have yet to figure that out, fully. (Witness the awkwardness of this week’s Colbert interview with the GOP front-runner.) But there’s one member of the media that claims to know exactly what Trump is, and what he could become: South Park. The topic of last night’s show—which, like the “P.C. culture” episode last week, generated a lot of pre-air buzz—was ostensibly immigration. The episode was more deeply, however, about Trump. He is much more than a passing whim, the episode argued. He could become dangerous. He could become president.

The gist of the episode is this: Canadians have immigrated to Colorado. They have brought with them their foreign customs (politeness, the rampant use of the word “buddy,” a tendency to put maple syrup on pasta), in response to which the people of South Park are predictably indignant.

Mr. Garrison, awash in a nativist rage—and wearing a “Where My Country Gone?” baseball cap—takes it upon himself to travel to Canada to demand that South Park’s neighbor to the north take back its immigrants. He quickly discovers, however, that the Canadians have built a wall. To keep the Americans out.

A further discovery (obtained when Mr. Garrison infiltrates Canada by traveling through Niagara Falls in a barrel): Canada, as we know it, has been destroyed. Ottawa looks like what might happen if Cormac McCarthy discovered GeoCities. Buildings slump in disrepair. Trash tumbles through abandoned streets. The population has fled. Apocalypse, it seems—Canadapocalypse—has come.

There is only one building that gleams among all of this destruction: a towering skyscraper that appears to be plated in titanium. Mr. Garrison rides an Escher-esque series of escalators to the building’s penthouse. Inside, he finds … President Trump.

Not Prime Minister Trump, mind you. President Trump. They exchange words. South Parkian hijinx ensue.

Here, though, is the heart of the episode—the scene that distills all the satire into one political message. One of South Park’s Canadian immigrants—who are also, it’s becoming clear, Canadian refugees—explains over a dinner of poutine and pie how President Trump happened. And, by extension, how Canada met its dystopian fate.

Holding back tears, the well-dressed refugee recalls,

There were several candidates during the Canadian elections. One of them was this brash asshole who just spoke his mind. He didn’t really offer any solutions, he just said outrageous things. We thought it was funny.

His wife sobs, hugging her young son.

He continues:

Nobody ever thought he’d be president! It was a joke! We just let the joke go on for too long. He kept gaining momentum, and by the time we were all ready to say, “Okay, let’s get serious now, who should really be president?” he was already being sworn into office. We weren’t paying attention! We weren’t paying attention!

He breaks down, weeping. The whole family weeps. Everyone weeps.