I think mathematically the worst bad beat ever is this guy with 4 aces losing to a royal flush in the WSOP a couple years ago:

You must be a registered user with confirmed email address to view this content.
Register or Login

 

Hypothetical: you hold a pocket pair and flop a set. Two other players flop straight flush draws...one high and one low. By the river, you make your quads and they make their SF. There is over $100k in Bad Beat Jackpot to be had. Who gets screwed? Obviously, not as devastating as a $450k+ cash pot, but for low-limit players, it's about as bad beat as you can get...if it gets determined as I think it does.

 

I experienced something similar years ago. On the river, two people had quads and one person had a straight flush. It was determined the straight flush and the highest quad qualified for the badbeat jackpot. The lower quads got table share with the others.

In your example, the two straight flushes would be the badbeat jackpot hands. The quads would be out of luck.

 

Sad to say these were before BB jackpots.

 

Keeping with the badbeat jackpot theme, this is from a small Indian casino about 12 years ago.

They had just started to spread NL games and the badbeat jackpot was about $30k and AAAQQ qualifier (I know, very low). The board was AAKQx, one player had AK and one had AQ. At showdown, the AQ guy sees he is beat, shows everyone his cards and mucks them. He didn't know about the bad beat and cost himself $15k as well as all the cash for the others at the table.

He was a young college kid, so after buying in for $40, $15k would have been a good ROI