Utg Limps

Hero pots to 50 with KsTsQcTc on BTN(Eff stacks 600)
BB,Straddel and UTG calls.

Flop: 3c4d5c, gets x around

Turn: Kc, all x to hero who bets 80 into 200, Straddle x-r to 320. Hero jams.

Lag is former online reg who now plays for fun, he is aggresive and capabel off bluffing. I do have nutty image but made this small bet
hoping it would be thought off as weak. I suppose its automatic gii?