...a dog playing chess with its owner. So he says, "What a remarkably intelligent dog!", and the owner replies, "Not really, he's lost the first two games."
Tim Vine writes a lot of this kind of one-liner. Most of the gags on this page are by him, esp. the ones lower down. He's a regular on ITV's The Sketch Show, which is starting next week I think. He's also on tour this year.