The real representation of Spitfire! He regards Spit as someone he wants to take care of, which is why he's in a glass tube, but as much as he wants to do that he is also limiting how much of an effect Spitfire has on him. Which is why there was the black frost- it blocked most of the light from the rest of the room, which was blocking Spitfire's influences on him. Cleaning it off would have made him more willing to talk to Spitfire about his deeper problems and worries.