void OnTriggerEnter2D(Collider2D collision)
{
// this is where it finds the player that collides with the upgrade
if (collision.CompareTag("Player"))
{
PlayerController2D player = collision.GetComponent <PlayerController2D>();
player.CurrentHealth = player.GetMaxHealth();
PS.Play("P_Heal");
GetComponent <SpriteRenderer>().enabled = false;
GetComponent <ParticleSystem>().Play();
Destroy(this, GetComponent <ParticleSystem>().main.duration);
}
}