A little help from my mutant muppet friends
This video has it all: Beatles + Muppets and creepy voice manipulation.
[youtube=http://www.youtube.com/watch?v=vnV-cTMAPL4]
Created by Columbia audio researcher Dan Ellis. Maybe he'll tell us how he did it some day.
Andy Baio points me to the original:
[youtube=http://www.youtube.com/watch?v=JjfdfU-uaPQ]