From
http://www.dictionaryofgambling.com/gambling_terms/all_gambling_terms/b/Bad-Beat Story [Poker]
A story told by someone who lost a pot, often a big one, in a bad beat.
Usually no one but the teller is interested in hearing the story. <LOL> 
The analog in the fishing world is the one that got away.

Whilst looking for this I found this page
http://askmrpokerperson.blogspot.com/2005_12_01_askmrpokerperson_archive.html which is mildy amusing on a Friday. It goes like this:
Dear Mr. Poker Person,
What is the origin of the term “runner-runner?”
Boston Sam
Dear Sam,
With a masters degree in Linguistics from the highly prestigious University of Chicago (are you impressed?), Mr. Poker Person is the perfect source for information like this.
“Runner-runner” is from the Polynesian runna-runna meaning “lucky bastard who just sucked out on me and whose luck is going to change just as soon as I get my hands on his scrawny little neck!”
Interestingly, the phrase “to catch runner-runner” originally referred to an ancient ritual wherein an overly lucky opponent was hunted down and his testicles cut off. (Sucking out is taboo for poker-playing Polynesian women. Aren’t primitive cultures just so quaint and adorable! Mr. Poker Person thinks so, too.) The offender's parts were then stuffed down his throat, extracted via his rectum using a Garden Weasel™ and fed to pigs. As you can see, the meaning of this phrase has changed over time. Like bad beats in poker, this kind of thing happens all the time in languages. Get over it.
By the way, "sucking out" comes from the Indonesian sookang gat which refers to a form of ESP whereby a person has a premonition of a soon to occur event that is both highly desirable and highly unlikely, as in "I called your large bet even though I only had one out and insufficient odds because I just knew I'd catch the case ace on the river."
As always, remember to stay out of the muck.
Your friend,
Mr. Poker Person