<Tr> <Th> Written by </Th> <Td> Trey Parker </Td> </Tr> <Tr> <Th> Production code </Th> <Td> 306 </Td> </Tr> <Tr> <Th> Original air date </Th> <Td> July 7, 1999 </Td> </Tr> <Tr> <Th_colspan="2"> Episode chronology </Th> </Tr>

Where did the phrase sad panda come from