A fart trapped in a toilet by its lid and discovered later by an unsuspecting user.

Named after the keystone miners of Pennsylvania who would go deep in the coal mines and shit in buckets. The smell would linger long after the mines would be closed.
"OMG, Matt, that's disgusting!!"

"Oh, sorry about that keystone kettle Kathy."
by ToeBang August 30, 2016
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