Reverse trigger

    //size of bullet
    public Vector2 bulletSize;
    //position of bullet
    public Vector2 bulletPos;
    //offset the colliders position by an amount
    public Vector2 colliderOffset;
    //what layers you want your collider to check with
    public LayerMask hitLayers;

void Update () {
        //gets the position of the bullet and adds the offset
        bulletPos = gameObject.transform.position + colliderOffset;
        //checks if any objects under a box and puts them all in a collider array named hitZone
        Collider2D[] hitZone = Physics2D.OverlapBoxAll(bulletPos, bulletSize, 0, hitLayers);
        //for each item in the hitZone array it will run the fullowing script
        foreach (Collider2D collider in hitZone)
        {
            //compares the collider's gameobject's layer to what you set it as (replace with your specific layer)
            if (collider.gameObject.layer == >>>ReplaceThis<<<)
            {

            }

        }