The South Park episode 'Insheeption' parodies the theories behind the recent Christopher Nolan film Inception, and includes the line "Sometimes my thoughts of my dead wife manifest themselves as trains."
However, it was revealed that creators Trey Parker and Matt Stone had unintentionally copied the line from a skit on the website CollegeHumor, after mistaking it as being quoted directly from the film itself.
"It's just because we do the show in six days, and we're stupid and we just threw it together," Stone explained. "But in the end, there are some lines that we had to call and apologise for."
Dan Gurewitch, a co-writer of the CollegeHumor sketch, later confirmed on his blog that Stone had apologised and claimed that "all is well".