That wallet was one held by none other than "Jewels" played by Samuel L. Jackson in the movie Pulp Fiction. And he was certainly a Bad MO FO.
I believe this to be a quote from the movie or something close to it: Jewels says to the robber in the diner cause he can not find in the bag with other stolen wallets in it - "It's the wallet that says Bad Mother Fucker on it". You have to watch that movie 5 times to get it and even then this movie changes each time I watch it.
Added, guess I should have looked at the link first.