The fact that Vandal Savage feels no pain is WTF enough, but the uber-rogue makes the statement here by referencing how it was Robin of Loxley who taught him such a skill. Robin of Loxley, of course, is better known as Robin Hood, a character who has often been referred to when poking fun at Green Arrow over the decades. It was most definitely a cool moment to see Savage simply remove one of Ollies arrows from his chest, and the idea that he is impervious to pain again reiterates the notion that this is a villain who is not to be messed with.