"YAAAAAAA-HOO-HOO-HOO-HOOOEEEYYYY!!!"He was kind enough to make a compilation of Goofy Hollers, a la The Wilhelm Scream Compilation. See the video and read a bit more here!
Recognize that onomatopoeia? It's the famous "Goofy Holler"!
The Goofy Holler's debut was in the 1941 cartoon The Art of Skiing, originally recorded by a professional yodeler by the name of Hannes Schrolle. Since then, it has become a staple of the history of cartoon sound effects and voices.