I once read this sci-fi book called "Hyperion", by Dan Simmons. In it, there are some creatures which always return after they die, because of a cross-like organ on their chest. however, in resurrection, they are stupid and have blue fur. In a sequel to this book, the intergalactic church used the crosses on people to resurrect them repeatedly, but it was altered so they wouldn't suffer any side effects. Just about the only way someone could be killed for good while having the cross was to be in the middle of a nuclear explosion. I think that Kenny has one of these crosses, and that's why he comes back. (Of course, if Matt and Trey are patrolling this NG, we'll probably see Kenny get killed by a nuclear explosion, making this theory worthless...)
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"Uh, okay, but ya only got 5 minutes. This place is turning into a Starbucks."
" Ahhh, There's nothing like a cigarette... unless it's a cigarette lit with a $100 bill!"