One of my favorite characters is also one of the rarely seen. He would always pop up from time to time and always cracked me up. He was always informative and very entertaining! May I present for your viewing pleasure, Professor Ludwig Von Drake!
"An Adventure in Color" (1961)
"The Spectrum Song" (1961)
"Music For Everybody" (1966)
"Snore Along with Ludwig"
"A Symposium on Popular Songs" (1962) directed by Bill Justice
(sorry, looks like the video is a bit slower than the audio at times.)