Strange continues to talk, as if this is a totally normal point of conversation, as he puts pressure on his scratch, holding the napkin tight to his palm to slow the bleeding.

"No, I just wanted to see how the head was growing. I've never met an animal that grew another head before, I wanted to see just what the process entailed."

He was nosy. That's the answer right there, Strange was being too nosy for his own good.