I know exactly how it could work in PvP. I spent literally 4 months creating a subclass with that concept, I just haven't gotten around to posting it since players would rather see a Fourth Class over a Dark Subclass. Either way, I love the mind trick idea and it should definitely be a thing in Destiny. Imagine hitting someone with a Hysteria ability then the target sees his allies as foes and enables team damage. Upgrades can either make the target see you as an ally, or have his allies be able to see him as a threat and turn on him first.