I'm a little confused as to the HH format and how much money went in on the flop, but I think there are two decent lines here. One is call, which keeps the pot small in case a scare card comes (which is unfortunately difficult to play when villain can have any 2) and also induces bluffs out of him on future streets. The other is to raise 3/4-full pot, which would probably take it down right there unless the guy has a monster or is a retard (which sounds quite possible).

You didn't say anything about postflop reads (i.e. what this kind of betting might indicate - is he usually a calling station, then throws out river bluffs frequently? Or is he aggro the whole way through?) but if his flop action here is typical, you're ahead most of the time.