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Скрипт
var monstr : GameObject;
function Start () {
monstr.active = false;
}
function OnTriggerEnter(other : Collider){
if(other.tag == "Player");
monstr.active = true;
}
function OnTriggerExit(other : Collider){
if(other.tag == "Player");
monstr.active = false;
Destroy(monstr);
}