This guy is probably a fishy chinese reg. I've really played vs lots of them and all are very strange and doing sometimes incredible idiotic moves. I really think the same about chinese as mbml saying about russian. :-)
I completly understand 3bet here is not such a good move preflop, but I was kinda in tilt when that opp some hands before got stupid moves and won pretty huge pots from me. And also I expect him to call preflop tonn of worth suited hands, so actually 3bet in position isn't so bad.
Spoiler

Grabbed by Holdem Manager
NL Holdem $0.25(BB) Replayer
SB ($38.95)
Hero ($25.68)
UTG ($9.30)
UTG+1 ($14.60)
CO ($29.60)
BTN ($31.36)
Dealt to Hero K♣ 3♣
fold, fold, fold, fold, SB raises to $0.75, Hero raises to $2.25, SB calls $1.50
FLOP ($4.50) 3♠ 3♥ 5♠
SB checks, Hero bets $2.25, SB calls $2.25
TURN ($9) 3♠ 3♥ 5♠ 8♣
SB checks, Hero bets $5.50, SB calls $5.50
RIVER ($20) 3♠ 3♥ 5♠ 8♣ 8♠
SB bets $15, Hero raises to $15.68 (AI), SB calls $0.68 wtf?