one object triggers another ( neither object the player)

I have an object a child of the player called "crosshair" and tagged as such. the object is in front of the player so when THAT hits the trigger zone( not the player) I want the animation on the game object called and tagged "dancertest" to play. But I can't get it to work and can't understand why. If I substitute "player" in the script like so at at he end...... if(other.tag == "Player") instead of if(other.tag == "crosshair") the player then triggers the animation I want. So what am I missing here? Everything seems to be in order or substituting that one word wouldn't work either. This object called "crosshair" has a box collider on it, name and tag match script

 using UnityEngine;
 using System.Collections;
 
 public class InAim : MonoBehaviour {
     GameObject crosshair;
     GameObject dancertest;
     Animation animation;
 
 
     void Start () {
         crosshair = GameObject.FindWithTag("crosshair");
         dancertest = GameObject.FindWithTag("dancertest");
         //animation = GameObject.GetComponent.("dancertest")<Animation>();
     }
     
 
 
         void OnTriggerEnter (Collider other) {
             if(other.tag == "crosshair")
             dancertest.GetComponent<Animation>().Play();
     
     }
 }