Here is a line test image from before the pilot we did for Dusty and Musty. This was quite some time ago now so when the client asked us to animate the mummy over a CG background we said of course we can. They wanted a test done of him walking down some stairs whilst carefully holding his canopic jar (it contains his insides) and at the same time Dusty (the dinosaur) is running around him trying to put him off. No problem we said. So we sent them 4 different panning speeds of the stairs to choose from and wouldn't you know, they wanted it the slowest speed but double as slow as we had it. What that meant is a lot more drawings and I dont remember the specific amount but it was over 600 drawings just for this character as he had a few levels and we had to animate it on 1's and didn't have any cycles (due to the acting).
When we did the series we animated it in Flash.