title: Make an object disappear from another object in Unity C#
body: <p>I'm trying to learn Unity and I want to make a simple game.I made most of the
  game but I am stuck in one place.When the player touches another object then a third object should disappear.I made the collision detection but I can't get the
  objects to communicate with each other.I tried gameObject.SendMessage but I 
  couldn't get the third object to receive the message.I looked for other ways of
  communicating between objects but I didn't understand them .I also tried running a script that makes the object disappear from the player object(I'm not sure it is possible)but it gave me some errors.
  i don't need the most efficient way I just need one that works and is simple</p>