RaycastHit.collider

Description

The Collider that was hit.

This property is null if the ray hit nothing and not-null if it hit a Collider.

 function Update() {
    if (Input.GetMouseButtonDown(0)) {
        var hit: RaycastHit;
        var ray = Camera.main.ScreenPointToRay(Input.mousePosition);

        if (Physics.Raycast(ray, hit)) {
            if (hit.collider != null)
                hit.collider.enabled = false;
        }
    }
}

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    void Update() {
        if (Input.GetMouseButtonDown(0)) {
            RaycastHit hit;
            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            if (Physics.Raycast(ray, out hit))
                if (hit.collider != null)
                    hit.collider.enabled = false;
                
            
        }
    }
}

See Also: Physics.Raycast, Physics.Linecast, Physics.RaycastAll.