Bizarre river raise

[private joker]

(This is Commerce 20/40 if it matters)

A fairly loose-aggressive player opens in EP; I 3-bet in the hijack with K[img]/images/graemlins/heart.gif[/img]Q[img]/images/graemlins/heart.gif[/img]. A very strange player takes 3 to the face on the button. He's been playing incredibly aggressive preflop and then spazzy post-flop, which often means checking monsters and semi-bluff raising the turn. It's hard to put him on hands; I guess he's a thinking LAG with FPS. Blinds fold, EP calls the 3-bet.

Flop comes 9[img]/images/graemlins/heart.gif[/img]7[img]/images/graemlins/diamond.gif[/img]5[img]/images/graemlins/heart.gif[/img]. EP checks, I bet, button calls, EP calls.

Turn brings 3[img]/images/graemlins/heart.gif[/img]. EP checks, I bet, both call.

River is the 3[img]/images/graemlins/diamond.gif[/img]. EP checks, I bet, button raises, EP folds, and I... ?