<Tr> <Td> </Td> <Td_colspan="2"> Pilot </Td> <Td_colspan="2"> March 1, 1994 (1994 - 03 - 01) / July 10, 1996 (1996 - 07 - 10) </Td> </Tr> <Tr> <Td> </Td> <Td> </Td> <Td> 20 </Td> <Td> October 7, 1996 (1996 - 10 - 07) </Td> <Td> February 14, 1997 (1997 - 02 - 14) </Td> </Tr> <Tr> <Td> </Td> <Td> </Td> <Td> 19 </Td> <Td> September 21, 1997 (1997 - 09 - 21) </Td> <Td> January 18, 1998 (1998 - 01 - 18) </Td> </Tr> <Tr> <Td> </Td> <Td> </Td> <Td> 20 </Td> <Td> August 31, 1998 (1998 - 08 - 31) </Td> <Td> March 8, 1999 (1999 - 03 - 08) </Td> </Tr>

What happened in the last episode of hey arnold