Something I see a lot is when I'm drawing OOP and HU with an opponent on the flop I will check and he will bet the min or 2x the minimum. I will call and then check on the turn and he will follow with the exact same sized bet. Then on the river he throws down a pot sized or slightly larger than pot sized bet.

These are always bad players making this move. What kind of hand do you generally think I'm up against? I think it's a set or some other big hand that was badly slowplayed.

Anyone have a different take on what this is?