I like this bluff. Based on the numbers, villain looks rather donkish to me. He is showing no real strength on this hand, except for the check raise on the flop. However, what I would expect to see in that situation is an over card trying to bluff at the pot and take it down right there, thinking you also had nothing.
If I was playing this hand against combu, and he called my check raise, I would pretty much automatically put him on either an over pair or a 10 with a good kicker (suited king or ace more likely) to warrant the preflop raise. A small set is also possible given his position in this hand. Either way, combu is repping strength.
What the donk looks like to me is a typical donk. Someone who does not think beyond what they have in their hand. These types of players don't really give much thought of what kind of cards their opponent has, nor do they even attempt to try and represent a hand they don't actually have. What this looks like from the villain is possibly a small pair or outright bluff thinking he can get you to fold. Players of this "caliber" don't understand pot odds
, fold equity, or any of the theoretical aspects of poker play. They only understand that hand X beats hand Y, and they think that any bet should suffice as a bluff. Donks certainly don't try and place a "raise me" sized bet here, as that is a level of sophistication far beyond what they are capable of.
The only thing I'm scared of if I make this bluff, is that the donk is oblivious to what I could be representing (ie a 10, overpair, etc). I've seen this so many times, that I am leery of outright bluffing donks now, just because they don't even understand when someone is making a move on them. This kind of reminds me of this time back in high school. My friend was a middle linebacker and was going to tackle a running back on the other team. The RB juked and my friend was toasted, except that the RB juked back the other way and got flattened, because my friend didn't even react to the jukes at all. Horrible play by my friend, but the point is that the RB got too tricky and it backfired on him.