Since there have been two responses that believe the first hand is a trap I'm curious about the reasoning behind it since I'm leaning towards a Kx. If I hit a boat on the turn I'd lean towards checking again since I would expect my opponent to bet out again. A free card here is unlikely to hurt me if he checks behind. If I hit trips on the turn I probably wouldn't bet ~3/4 of the pot when a 1/2 pot bet achieves the same means and is more likely to induce a bad call. I think this bet is trying to buy the pot because a boat doesn't worry about the flush or straight and trips can still lay bad odds to call the river along with having plenty of outs.