Sam: What are you up to? Sneaking off, are we?
Gollum: Sneaking? Sneaking? Fat Hobbit is always so polite. Smeagol shows them secret ways that nobody else could find, and they say "sneak!" Sneak? Very nice friend. Oh, yes, my precious. Very nice, very nice.
Sam: All right, all right! You just startled me is all. What were you doing?
Gollum: Sneaking.