Why is “Come Back Here I wanna kill you!” so funny?

Let me elucidate the context first. I was watching a let’s play – a video with commentary – of the game Skyward Sword by one of my friends. In this particular episode he is traversing lethal lava (land) on a ball and at one point he comes across an enemy who shoots fireballs towards the main character. He decides to chase this enemy and then shouts “Come back here I wanna kill you!” And I laughed pretty hard. (By the way he kills the enemy soon after, thus causing health to appear.) I’d like to know – or derive some conclusion about – why. There are multiple factors at play. For one, there is the whole revenge on an enemy, the comical nature of the situation in his slippery attempts to chase the enemy down; but there is also the fact that the enemy tried to scamper away (swimming in the lava, of course). Finally, and the most obvious, my friend may have just shouted the words at the “right” speed and volume to make them funny. These are all possibilities, but I’d like to think that the sheer irony of the situation is what makes it so funny. Multiple ironies exist, one of them being the enemy becoming the hunted, or that he had to move away so gracelessly in what should be his home territory. As humans – or Hylians in Link’s case – we tend to get angry very quickly and seek revenge without considering any other alternative. But that’s besides the point. My friend expected to kill the enemy but the action was delayed slightly, resulting in this brief chase sequence as the enemy’s demise approached. Was that murderous impulse funny, ironic, or both? The action is in itself quite humorous but there is a greater irony that arises due to its humor: humans find their act of revenge to be quite supreme, and even if it is justified, still the human drives forth trying to exact it. Is that why it’s funny? Some cosmic human failing? I don’t know, but it was pretty funny.