Clark could pinpoint the moment, down to the second, that he truly knew he was an alien. Intellectually, he realized that they were telling the truth, but he didn’t understand it – not yet. He didn’t feel it when his parents told him or when they showed him the ship or in the cemetery later that night or in Reilly field the next day

Clark actually hadn’t really know that he was – for certain, without any doubt— an alien for several months after that. He didn’t know it, in his heart, until his father’s shotgun blast struck him square in the chest – leaving a spattering of quarter-sized bruises… but no other visible scars. He knew that Jonathan had been driven to violence by the Nicodemus plant’s spore; but, sometimes in the late night quiet, Clark still wonders if Jonathan would have shot a human son.