This South Park episode was originally aired on 4th February 1998
In this South Park episode Eric Cartman is handing out invitations to his birthday party at school. Mr. Garrison informs them all that there is a new student joining the class. Announcing to all that he is Damien, the son of Satan. Even as Damien demonstrates his demonic powers the children are more loathsome than impressed.
According to the DVD commentary, Pip was originally supposed to die in this South Park episode but they decided not to kill him off because they needed him for crowd scenes.
South Park Spoiler Alert!
(The complete plot for this South Park Episode)
Cartman is excited about his upcoming birthday party and lets everyone invited know what present he expects to receive from each - and when they protest, he threatens to ban them from eating the food his mother makes, something that immediately convinces them. They encounter a new student named Damien, son of Satan, from the seventh circle of Hell. The other boys mock the "new kid" and, in response, Damien turns Kenny into a duck-billed platypus. Damien informs Jesus that Satan will rise for a final battle with him of good versus evil. South Park residents immediately begin making bets on the fight, which will be shown on pay per view for $49.95. Cartman is angered to learn the event is scheduled for the same time as his party, and the children struggle to choose between the two events.The entire town bets on Jesus to win the fight, but begin to lose faith when Satan appears for the weigh-in. He is huge and weighs a little over 320 pounds (150 kg), while Jesus weighs a mere 135 pounds (61 kg), and the citizens of South Park begin changing their bets. Jesus confronts the South Park residents about their changed betting slips after learning only one person is still betting on Jesus to win; furthermore, that one person is NOT father Maxi, the local priest. Distraught, Jesus asks Stan, Kyle and Chef to help him train. Damien gets counseling from Mr. Mackey, who recommends he just try being nice no matter what the other children do, like to the unpopular British child Pip. Damien tries to apologise to the boys for setting fire to the playground and turning Kenny into a duck-billed platypus, stating that he was "doing his father's bidding" and he did not have a choice. The boys however, still continue to act negatively towards Damien. Cartman's birthday party begins, as does the fight. Damien and Pip arrive uninvited to the party, but the children finally accept Damien after he hurls Pip in the air and makes him explode in a shower of fireworks. However, Cartman ends his party early and kicks everyone out after opening Kyle's present to discover that Kyle didn't buy him the present he was asked to get (due to the fact that they were all out of them).
Meanwhile, Jesus is disheartened by the town's lack of faith in him, and he does not retaliate to Satan's attacks against him, despite Satan's apparent taunting of "hit me!" Chef and the children make it for the end of the fight and offer Jesus some words of encouragement. Inspired, Jesus finally throws a single weak punch. However, Satan then takes a dive and goes down for the count. Afterward, Satan reveals that his plan had, in fact, been to bet on Jesus and then throw the fight, winning him a lot of money and real estate from the South Park residents. The townspeople are angered by this, until Stan reminds them that Jesus told them not to bet on him. The whole town then asks forgiveness of Jesus, who accepts the apology. Kenny dies when Jimbo identifies him as a rare duck-billed platypus and shoots him. Damien bids goodbye to Stan and Kyle since his dad "is always on the move" he has to leave. Stan and Kyle feel sympathy for Damien and state that "parents can be so cruel." Meanwhile, Cartman has continued his party even after kicking everyone out and eaten all the food himself.