Legolas kills a wolf

Gandalf stood up and strode forward, holding his staff aloft. ‘Listen, Hound of Sauron!’ he cried. ‘Gandalf is here. Fly, if you value your foul skin! I will shrivel you from tail to snout, if you come within this ring.’

The wolf snarled and sprang towards them with a great leap. At that moment there was a sharp twang. Legolas had loosed his bow. There was a hideous yell, and the leaping shape thudded to the ground; the Elvish arrow had pierced its throat. The watching eyes were suddenly extinguished.

The Fellowship of the Ring, Book Two, Chapter 4: A Journey in the Dark.