More than any other show in TV history, perhaps, The Simpsons has given audiences the largest array of unforgettable characters.
Because the main players in this sitcom phenomenon have ingrained themselves in modern pop culture to such an extent that characters such as Homer Simpson and Moe the Bartender are recognisable to millions of people the world over - not just for their looks, but for their dense and rounded personalities, too.
So whilst endlessly interesting, comic characters such as Ned Flanders, Mr. Burns, and Principal Skinner have lit up our screens for hundreds of episodes, fleshing them out to the point that they feel like real people, The Simpsons also remains impressive for its distinct array of "one-time" only characters. Memorable creations who popped up for just 22 minutes, never to be seen again, but left one hell of a lasting impression.
The Simpsons wins all the prizes for having the best and most memorable one-time characters of any show ever, of course, but there are a choice few within this category who have reached a higher plain: those who appeared only once, and yet - through a combination of great writing and voice acting - have remained immensely popular with fans in the same way as the show's regular cast members...
Note: if a character appeared in a brief, wordless cameo or a background shot in later episodes, they're still eligible for inclusion on this list.