I think this is just a sentence to learn a word, nothing special. (now: rise of the potato believers)
Help! The horse is eating the holy potato!
That made my day, here's a lingot!
Ok I'll bite, what is this about? Is it some sort of expression, or idiom?
You might need to ask a question "Where is the _.".. from time to time. I try to look at the sentence structure, not necessarily the exact words in each sentence...
There are waaay too many hits on Google on this topic :-) Whoever wrote this sentence may have heard the story posted by the Nürnberger Zeitung in 2010 called "Oh You Holy Potato" referring to two seperate families who both cut into a potato to find the sign of the cross. What?!