#?: The horrible inconsistency of enemies. They'll have the exact same thing in two games but call it something else. Or they'll use the same name in two games for two completely different creatures. Or they'll translate the names from Japanese in one game but not in another. Or they'll have different names for the same enemy in the manual from the ones in the credits at the end of the game. It's enough to drive an indexer insane.
Lee "Mega 2" Sherman
Super Mario Bros. Indexer
http://angelfire.com/games2/marindex/index.html