Vamp is a character in a video game (best video game of all time) called metal gear solid, and he specialises in knives, has temporary immortality, and has fangs. Every time he stabs someone, he licks the knife clean and relishes in the taste. People originally though that vamp was short for vampire, but Solid Snake, the protagonist of the series said during a Codec radio transmission: "No, Vamp isn't short for vampire. It's because he's bisexual."
Now, I don't get that. How is Vamp a name for a bisexual person?!