Okay so this is from like 5 years ago, when we first instituted the blanket ban on religious discussions. Some users were very upset with us, and other users teased them by pretending to be outraged that they couldn’t talk about their “religion” Potatoism. Over time, that became the official fake religion of the forum. Potatoists believe in the Great Potato, who may one day deliver us to his starchy kingdom. It has since evolved into a long running joke or a way to get around the religion ban. Since the great potato isn’t a real religion, people sometimes invoke his name instead of referring to an actual deity. Sort of like pastafarianism.
Edited to add: I believe @Nomad gets credit for starting the potato thing