Unless he was getting cute pre with 64 then the only thing you need to worry about is a set. You MAY have wanted to just shove/reraise on the flop since he wants to get into a bidding war with you right there.

It could have been he figured you for a steal. When people c-bet and get raised they are, at times, thinking "oh, his only making a play. I'll show him". Not always, but sometimes.