Animating the position would be the easiest. First link the object to an empty gameObject, this is done because when you animate something the object will use those exact coordinates every time it plays so if you move the object or created a duplicate it will snap to those coordinates once played, but when it's linked to another object first it zeros out the x,y,z and uses the local coordinates so you can move it if you want. Select the animated object and open the animation window, then animate it moving down, then make another animation moving from down to the up position.

var animateObject : GameObject;

function OnCollisionEnter (col : Collision) {

yield WaitForSeconds(1);
   animateObject.animation.Play("upPOS-downPOS");

yield WaitForSeconds(3);
   animateObject.animation.Play("downPOS-upPOS");
}

function OnCollisionEnter (col : Collision) {

yield WaitForSeconds(3);
transform.position -= Vector3.up;
yield WaitForSeconds(3);
transform.position += Vector3.up;

}

moves 1m down after 3 seconds, then 1m up after 3 more seconds (added as an alternative to the good animation answer above)

I don't know Javascript, so this is going to be in C#, but I think it will be easy enough to understand that you can convert it.

You need to start a coroutine when it gets hit to do everything you want.

void OnCollisionEnter(Collision other)
{
     StartCoroutine(CollisionEvents());
}

IEnumerator CollisionEvents()
{
     // Send score here
     yield return new WaitForSeconds(1);
     // Hide here
     yield return new WaitForSeconds(5);
     // Show here
}