I didn't have terrible twos either, and I didn't have a child who tried to bite me or anyone else more than once. Naughty steps, withdrawal etc are no use unless the child understands her behaviour is unacceptable; an instant, really stern response and physical restraint to prevent biting, kicking, hair -pulling etc. She appears to think it funny, which suggests she is being indulged at home, possibly because she is the youngest, and 'Terrible Twos' is being used as an excuse. Discuss this behaviour with both parents, and then make it clear you will not tolerate biting, hitting, kicking etc, and stick to it.