Strage line from opponent

[Evan]

Party Poker 3/6 Hold'em (9 handed)

Preflop: Hero is MP3 with 7[img]/images/graemlins/club.gif[/img], 7[img]/images/graemlins/spade.gif[/img].
UTG folds, UTG+1 calls, MP1 folds, MP2 folds, Hero calls, CO folds, Button folds, SB folds, BB checks.

Flop: (3.33 SB) 4[img]/images/graemlins/club.gif[/img], 7[img]/images/graemlins/heart.gif[/img], Q[img]/images/graemlins/spade.gif[/img] <font color="blue">(3 players)</font>
BB checks, UTG+1 checks, <font color="CC3333">Hero bets</font>, <font color="CC3333">BB raises</font>, UTG+1 folds, Hero calls.
Kind of a wierd check-raise since no one showed any aggression preflop. I'm obviously planning to raise when he leads the turn.

Turn: (3.66 BB) 3[img]/images/graemlins/spade.gif[/img] <font color="blue">(2 players)</font>
BB checks, <font color="CC3333">Hero bets</font>, BB calls.
Okay, now I'm confused...check-raise, check-call? I have no idea what he has.

River: (5.66 BB) 8[img]/images/graemlins/diamond.gif[/img] <font color="blue">(2 players)</font>
<font color="CC3333">BB bets</font>, <font color="CC3333">Hero raises</font>, <font color="CC3333">BB 3-bets</font>, Hero calls.
I don't really see how that 8 could've helped him unless he has 88. This line makes no sense for a straight since he would've made it on the turn. What the hell does he have? I don't know, so out of confusion I call the 3 bet. Should I cap on a river like this when he comes to life?

Final Pot: 11.66 BB