No Mr 999 troll. Paranoid I said and paranoid I meant. You're thinking of schizophrenia, which Wikipedia defines as "a mental disorder characterized by a breakdown of thought processes and by poor emotional responsiveness". It does, I believe, sometimes manifest itself as a tendency to assume multiple identities and social roles. As such it probably explains that strange characteristic of the Mudcat troll; a tendency to log on as a guest, but using using multiple aliases.