"wog" is banned. I had a shiny poliwhirl I wanted to name "Boss Wog", you know, like poliwog? I opted for "BOSS W0G".
"beaver" is banned if you don't put a character right after it, i.e., you can't name your Bibarel "Beaver", but you CAN name it "Nice Beaver!"
"Penelope" is banned, which blows, because it's such a nice female name.
