"That won't happen to me." It's an absolutely lame answer, especially considering that it could happen in the first place. He can't remember the source, but Strange knows he's read something of people changing the more time they spend in the land of faerie, their bodies adapting and changing to fit the surroundings, gaining things like feathers and scales, someone's eyes turning into mirrors.

But that just straight up hadn't occurred to Strange until Childermass pointed it out. He was far too arrogant to think otherwise.

"But if it does, then I'll simply have to prove my use in other ways. I've more spells in my arsenal than you realize, changeling."