I meant to post a topic for this a long time ago...
This old episode of Pokemon features a gas that makes everyone's voice high-pitched:
http://pokemonepisode.org/episode-54...the-k-9-caper/ (starts around 11:44)
I also found the Japanese version:
http://www.bilibili.tv/video/av141618/index_54.html (around 12:04)
There's a lot of high-pitch stuff in shrinking material, of course, but all I can think of right offhand is
this old text-to-speech file.
Anyone else got anything like this? It's always been a favorite of mine.