Fire is the whole story here. It begins small, almost gentle: heat at a man's feet that is "just bearable," barely a warning. Then it climbs, and the repeated "up and up and up" makes the spread feel unstoppable. By the time it reaches his hair and lips, it has become an inferno he never saw coming.
The middle of the poem breaks into short, panicked questions: "what happened? where did this come from? how did it start? who?" They read like the thoughts of someone in shock, grasping for an explanation while the damage is already done. The final word, "who?", hints at blame, though the poem never says whose fault it is.
The last two lines turn bleak. His answers are only "screams / tainted in ashes," so the questions go unanswered. The mood is frightening and helpless. The title, "Ancient Artifact," suggests the fire may be more than literal, perhaps an old hurt or anger, but the poem leaves that open.