Good call, sick beat

[sjay2k]

Was playing a $200 headsup SNG (NL) on Pacific last night.

I have AsKs on the button, blinds are 15-30. I make it 100. My opponent (pretty straightforward pre-flop, pretty damn aggressive postflop) calls. Chipcounts are, funnily enough, dead even.

Flop is 2s-4d-4h (pot: 200).

Villain bets 100, I raise to 240, Villain calls.

Turn is 3h (pot: 680).

Villain pushes for 660 (!).... WTF? What's he trying to sell here? No way he open-jams with the wheel or trip 4s. Other than 55 or A3, I can't think of any hand that I'm beaten by here. I call.

Villain shows Ad-7d.

River 7h, gg sir.