100NLAKo weird pre-flop action; a cold caller shoves over 3bet; call?

[Lego05]

Main villian is 33.9/11.86/.81

So by my math I'm getting ~1.35 to 1. What the hell is this guy doing? And am I calling this?

PokerStars No-Limit Hold'em, $1.00 BB (5 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Hero ($100)
BB ($74.90)
UTG ($106.85)
MP ($171)
Button ($141.30)

Preflop: Hero is SB with A[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/diamond.gif[/img].
UTG calls $1, <font color="#CC3333">MP raises to $4</font>, Button calls $4, <font color="#CC3333">Hero raises to $18</font>, <font color="#666666">1 fold</font>, UTG folds, MP folds, <font color="#CC3333">Button raises to $141.3</font>, Hero ???