Fold this?

[Nacarno]

It was pretty early in the tournament but the CO seemed pretty loose.

PokerStars No-Limit Hold'em Tourney, Big Blind is t20 (9 handed) converter

MP1 (t1580)
MP2 (t1480)
MP3 (t1400)
CO (t900)
Hero (t1910)
SB (t1380)
BB (t1500)
UTG (t1200)
UTG+1 (t2150)

Preflop: Hero is Button with K[img]/images/graemlins/heart.gif[/img], Q[img]/images/graemlins/spade.gif[/img].
UTG calls t20, <font color="#666666">2 folds</font>, MP2 calls t20, MP3 calls t20, CO calls t20, Hero calls t20, SB completes, BB checks.

Flop: (t140) K[img]/images/graemlins/club.gif[/img], 8[img]/images/graemlins/club.gif[/img], 5[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(7 players)</font>
SB checks, BB checks, UTG checks, <font color="#CC3333">MP2 bets t20</font>, MP3 folds, CO calls t20, <font color="#CC3333">Hero raises to t140</font>, SB folds, BB folds, UTG folds, MP2 folds, CO calls t120.

Turn: (t440) J[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">CO bets t80</font>, Hero ???

The CO's bet here really confused me. I couldn't think of many hands here that'd he'd suddely bet that I had beat and calling only to fold to a river bet seemed pretty weak. Agree?