Maybe not a tremendous bad beat, but a jaw-dropper for me.

Party Poker 1/2 Hold'em (10 handed)

Preflop: Hero is MP1 with , .
3 folds, Hero raises, 1 fold, MP3 calls, 2 folds, SB calls, BB calls.

Flop: (8 SB) , , (4 players)
SB checks, BB checks, Hero bets, MP3 calls, SB calls, BB folds.

Turn: (5.50 BB) (3 players)
SB checks, Hero bets, MP3 calls, SB calls.

River: (8.50 BB) (3 players)
SB bets, Hero calls, MP3 folds.

Final Pot: 10.50 BB

Results in white below:
SB has 8c 5c (straight, eight high).
Hero has Ah Kd (two pair, aces and kings).
Outcome: SB wins 10.50 BB.

i actually would have raised the river as more often than not, he will have made a two pair that you beat. Hell of a beat though.

They were suited, I can't blame him