A nasty fellow with solid leadership. If he is the one with the highest leadership abilities in your team, he will be your Team Leader. This may have a very small negative effect on team spirit due to the Anticlown's nasty nature. The effect may be bigger if your Coach has low leadership abilities.
However, as with the Clown, there has been no widely convincing proof for that kind of effect so far. We must assume the effect is there, because it is stated clearly in the rules, even though it is almost immeasurably small.