'Set the mob to "dead" mode. This turns it off
and makes sure it can take no more damage.
It also starts a ticker for when it will return.'

def set_dead(self):

    self.db.is_dead = True
    self.location = None
    self.ndb.is_patrolling = False
    self.ndb.is_attacking = False
    self.ndb.is_hunting = False
    self.ndb.is_immortal = True
    self._set_ticker(self.db.death_pace, 'set_alive')
