Goobacks [SEP] series
Goobacks
"Goobacks" is the seventh episode of the eighth season of the animated television series "South Park", and the 118th overall episode of the series. It originally aired on Comedy Central in the United States on April 28, 2004. 
In the episode, people from a poverty-stricken future year of 3045 travel back in time to find work, via a recently discovered time portal. When the boys try to earn some extra money, the time-traveling immigrants are willing to do the same work
, plant trees, give to the poor, etc., hoping to cause the Goobacks to disappear. Although the townspeople's efforts are successful and the Goobacks begin to fade away, the boys observe that the work is "gayer than all the men getting in a big pile and having sex with each other", and with an exclamation of "We're sorry, back in the pile!", the male adults including the boys happily resume their orgy.
Home release.
"Goobacks", along with