Cannibal!: The Musical Easter Egg - It's Really Trey

Well this is boring, and I'm sure you all know this, but Alfred Packer is played by Trey Parker, but he credits himself as Juan Schwartz, as "Trey Parker" is listed as the Director, one of the producers, one of the sound engineers, script writer, song writer, etc. and didn't want it to look like a one man show.

Also, the Judge is played by Trey's Dad, Randy, who Stan's Dad, Randy, is modelled off in South Park. Notice the similarities.