Cher started that garbage about 4 or 5 years ago -
it's pitch
 correction taken to extremes.
 
 Cher could not have been the first to popularize this.  I am pretty sure
 that boy band Simpsons episode predates "Believe".
 (BTW I can't stand the effect either) 
 
 I'm not sure I've heard this effect... what other songs have used it?