River a straight, pfr takes a wierd line (NL100)

[CalledDownLight]

I have no read on this clown, so I'm not really sure what to do. If you say fold what are you putting him on with his c/c flop, check turn line?

Poker Stars, $0.50/$1 NL Hold'em Cash Game, 8 Players
LeggoPoker.com - Hand History Converter

BTN: $96
SB: $99
BB: $77.20
UTG: $101.90
UTG+1: $99
MP1: $110
MP2: $172
Hero (CO): $129.55

Pre-Flop: 8[img]/images/graemlins/heart.gif[/img] 8[img]/images/graemlins/spade.gif[/img] dealt to Hero (CO)
2 folds, <font color="red">MP1 raises to $4</font>, MP2 folds, Hero calls $4, BTN calls $4, 2 folds

Flop: ($13.50) 7[img]/images/graemlins/diamond.gif[/img] T[img]/images/graemlins/heart.gif[/img] 7[img]/images/graemlins/spade.gif[/img] (3 Players)
MP1 checks, <font color="red">Hero bets $10</font>, BTN folds, MP1 calls $10

Turn: ($33.50) 9[img]/images/graemlins/spade.gif[/img] (2 Players)
MP1 checks, Hero checks

River: ($33.50) 6[img]/images/graemlins/spade.gif[/img] (2 Players)
<font color="red">MP1 bets $96 and is All-In</font>, Hero ???