We all know no self-respecting players will work in a team, unless there's a inmidiate advantage of it. So I thought of giving people a small advantage when being near teammates, like better aim, less stamina drain ,faster healthregeneration, etc.
I also though of some alien attacker who could fold itself up in a pantsered form with a big turning circle and fold itself out in a slower, faster turning slicing and dicing machine. So you could fold up and storm into human defenses, unable to attack but taking little damage and then fold out to do damage upclose but you'd be a lot more vulnarable.
ok, bye now.