 The first season finale, "Cartmans Mom is a Dirty Slut", ended on a  cliffhanger in which the identity of Cartmans father was to be  revealed. But Trey Parker and Matt Stone played a joke on the  viewers with the second season opener, "Terrance & Phillip in Not  Without My Anus" which aired on April Fools Day. Instead of  revealing the identity of Cartmans father, the episode was all  about Terrance & Phillip trying to stop Saddam Hussein from taking  over Canada. As a result, Comedy Central was flooded with phone  calls from angry viewers. They were outraged that the cliffhanger  was not resolved after waiting for five weeks. Viewers became even  more outraged when they learned they had to wait another three weeks  for the next episode in which the identity would finally be  revealed. This notorious episode has rarely been rerun since.