I saw a team led by teebo, who I believe can apply stealth to other characters when they take damage. I found it extrememly difficult to beat as when you targeted a specific enemy, they would stealth and you were forced to attack another character. This gave them time to heal. I've only seen one team like this and I believe it was set up pretty bad, but if set up well it can be very devastating. That being said I don't think an entire team of stealth characters would be very beneficial as once they are all cloked they may as well not be clocked at all. Imo a strong Cloke+heal team