rivered nut flush on double paired board

[RockRattler]

Villain seems like a donk - he is running at 40/20/1.8

Party Poker, $0.25/$0.50 NL Hold'em Cash Game, 6 Players
LegoPoker Hand History Converter

CO: $40.13
BTN: $63.90
SB: $30.64
BB: $107.84
Hero (UTG): $54.97
MP: $50.68

Pre-Flop: Q[img]/images/graemlins/heart.gif[/img] A[img]/images/graemlins/heart.gif[/img] dealt to Hero (UTG)
<font color="red">Hero raises to $2</font>, 3 folds, SB calls $1.75, BB folds

Flop: ($4.50) 2[img]/images/graemlins/heart.gif[/img] K[img]/images/graemlins/diamond.gif[/img] K[img]/images/graemlins/heart.gif[/img] (2 Players)
SB checks, <font color="red">Hero bets $3</font>, SB calls $3

Turn: ($10.50) 2[img]/images/graemlins/spade.gif[/img] (2 Players)
SB checks, Hero checks

River: ($10.50) 4[img]/images/graemlins/heart.gif[/img] (2 Players)
<font color="red">SB bets $25.64 and is All-In</font>, Hero ?