LOL, he used to be a Pokemon fan, and his favorite was Pikachu, which everyone else used as his nickname.

However, he and I had a running argument over whether or not Pikachu had fur or not, with me firmly in the furred camp. Therefore I twisted his nickname to Furball to annoy him.

I never call him anything else now, he is even in my e-mails and phone as Furball! lol.