CODE EXAMPLE FOR CSHARP

Unity Destroy gameObject upon collision

void OnCollisionEnter2D(Collision2D collision)
{
    Destroy(gameOnject);
}

// Or if you only want it to be destroyed when 
// hitting something specific

void OnCollisionEnter2D(Collision2D collision)
{
    if(collision.gameObject.tag == "tag")
    {
         Destroy(gameObject);
    }
}