First aired in 1990-91, the second series of The Simpsons proved that, far from being a one-joke sitcom about the all-American dysfunctional family, it had the potential to become a whole hilarious universe. The animation had settled down (in the first series, the characters look eerily distorted when viewed years later), while Dan Castellaneta, who voiced Homer, decided to switch from a grumpy Walter Matthau impression to a more full-on, bulbous wail. The series' population of minor characters began to grow with the inclusion of Dr Hibbert, McBain and attorney Lionel Hutz, while the writers became more seamless in their ability to weave pastiche of classic movies into the plot lines.