1984 "Athiest" Cud Cent, Lincoln Memorial Variety

(I apologize for the poor quality of the photos, for now as I'm mainly posting this as an educational source)
This is a Cud Cent, IE A die break which forms along the exterior of the coin's edge that leads to a large blob of material which obscures part of the pattern/edging of the coin. This is a fairly severe break (though much more severe cuds do exist) and, due to the fact that it obscures the word "God" from "In God We Trust" can be considered an "Athiest" variety. Some argue that only the original year (1976 if I recall correctly) to be the only true coin to bare this moniker; but the term itself is neither official and was "coined" (pun intended) by a numismatic periodical in order to garner hype for the discovery.

Cuds are swiftly becoming a highly sought after form of collectible error as, unlike most error coins,, they are extremely easy to identify, virtually impossible to counterfeit, and do not require expensive and questionably subjective grading/attribution services to buy/sell/trade with full confidence.