Donkbet on a Passive Table

[Angrymoog]

I'm also less inclined to give this guy credit for a K.

There's lots of possabilities, maybe hes betting becasue he now has two pair, or maybe hes trying to "bluff" you because youll perceive a king as a scare card if you dont have it, but youll raise if you do. I think the natural tendancy of a player with a King is to check-raise the turn, which even passive players can do.