South Park: Bigger Longer Uncut (1999). When the four boys see an R-rated movie featuring Canadians Terrance & Phillip, they are pronounced “corrupted”, and their parents pressure the United States to wage war against Canada.
Unlike a lot of other series, South Park didn’t wait until it had exited its prime to do a movie. This is such a great work of satire and one that does it’s broader canon proud. The songs are great, the animation super fun and the whole product pretty damn funny. Definitely one to check out (but maybe not so much if you’re a bit sensitive to un-PC jokes!) 8/10.