Authors:

If he smiled much more, the ends of his mouth might meet behind, and then I don't know what would happen to his head! I'm afraid it would come off!

Lewis Carroll (2016). “Alice In Wonderland Collection: All Four Books: Alice in Wonderland, Alice Through the Looking Glass, Hunting of the Snark and Alice Underground”, p.118, Enhanced Media Publishing
If he smiled much more, the ends of his mouth might meet behind, and then I don't know what would happen to his head! I'm afraid it would come off!