Decoy

n.
  1. Anything intended to lead into a snare; a lure that deceives and misleads into danger, or into the power of an enemy; a bait.
  2. A fowl, or the likeness of one, used by sportsmen to entice other fowl into a net or within shot.
  3. A place into which wild fowl, esp. ducks, are enticed in order to take or shoot them.
  4. A person employed by officers of justice, or parties exposed to injury, to induce a suspected person to commit an offense under circumstances that will lead to his detection.